In a fast-paced industry like tech, it can be hard to deal with the fear of missing out on important news. But, as many of us know, there’s an absolutely huge amount of information coming in daily, and finding the right time and balance to keep up can be difficult, if not stressful. A classic piece of technology like an RSS feed is a delightful way of taking back ownership of our own time. In this article, we will create a static Really Simple Syndication (RSS) reader that will bring you the latest curated news only once (yes: once) a day.

We’ll obviously work with RSS technology in the process, but we’re also going to combine it with some things that maybe you haven’t tried before, including Astro (the static site framework), TypeScript (for JavaScript goodies), a package called rss-parser (for connecting things together), as well as scheduled functions and build hooks provided by Netlify (although there are other services that do this).

I chose these technologies purely because I really, really enjoy them! There may be other solutions out there that are more performant, come with more features, or are simply more comfortable to you — and in those cases, I encourage you to swap in whatever you’d like. The most important thing is getting the end result!

The Plan

Here’s how this will go. Astro generates the website. I made the intentional decision to use a static site because I want the different RSS feeds to be fetched only once during build time, and that’s something we can control each time the site is “rebuilt” and redeployed with updates. That’s where Netlify’s scheduled functions come into play, as they let us trigger rebuilds automatically at specific times. There is no need to manually check for updates and deploy them! Cron jobs can just as readily do this if you prefer a server-side solution.

During the triggered rebuild, we’ll let the rss-parser package do exactly what it says it does: parse a list of RSS feeds that are contained in an array. The package also allows us to set a filter for the fetched results so that we only get ones from the past day, week, and so on. Personally, I only render the news from the last seven days to prevent content overload. We’ll get there!

But first…

What Is RSS?

RSS is a web feed technology that you can feed into a reader or news aggregator. Because RSS is standardized, you know what to expect when it comes to the feed’s format. That means we have a ton of fun possibilities when it comes to handling the data that the feed provides. Most news websites have their own RSS feed that you can subscribe to (this is Smashing Magazine’s RSS feed: https://www.smashingmagazine.com/feed/). An RSS feed is capable of updating every time a site publishes new content, which means it can be a quick source of the latest news, but we can tailor that frequency as well.

RSS feeds are written in an Extensible Markup Language (XML) format and have specific elements that can be used within it. Instead of focusing too much on the technicalities here, I’ll give you a link to the RSS specification. Don’t worry; that page should be scannable enough for you to find the most pertinent information you need, like the kinds of elements that are supported and what they represent. For this tutorial, we’re only using the following elements: , , , , and . We’ll also let our RSS parser package do some of the work for us.

Creating The State Site

We’ll start by creating our Astro site! In your terminal run pnpm create astro@latest. You can use any package manager you want — I’m simply trying out pnpm for myself.

After running the command, Astro’s chat-based helper, Houston, walks through some setup questions to get things started.

 astro   Launch sequence initiated.

   dir   Where should we create your new project?
         ./rss-buddy

  tmpl   How would you like to start your new project?
         Include sample files

    ts   Do you plan to write TypeScript?
         Yes

   use   How strict should TypeScript be?
         Strict

  deps   Install dependencies?
         Yes

   git   Initialize a new git repository?
         Yes

I like to use Astro’s sample files so I can get started quickly, but we’re going to clean them up a bit in the process. Let’s clean up the src/pages/index.astro file by removing everything inside of the

From there, we can spin things by running pnpm start. Your terminal will tell you which localhost address you can find your site at.

Pulling Information From RSS feeds

The src/pages/index.astro file is where we will make an array of RSS feeds we want to follow. We will be using Astro’s template syntax, so between the two code fences (—), create an array of feedSources and add some feeds. If you need inspiration, you can copy this:

const feedSources = [
  'https://www.smashingmagazine.com/feed/',
  'https://developer.mozilla.org/en-US/blog/rss.xml',
  // etc.
]

Now we’ll install the rss-parser package in our project by running pnpm install rss-parser. This package is a small library that turns the XML that we get from fetching an RSS feed into JavaScript objects. This makes it easy for us to read our RSS feeds and manipulate the data any way we want.

Once the package is installed, open the src/pages/index.astro file, and at the top, we’ll import the rss-parser and instantiate the Partner class.

import Parser from 'rss-parser';
const parser = new Parser();

We use this parser to read our RSS feeds and (surprise!) parse them to JavaScript. We’re going to be dealing with a list of promises here. Normally, I would probably use Promise.all(), but the thing is, this is supposed to be a complicated experience. If one of the feeds doesn’t work for some reason, I’d prefer to simply ignore it.

Why? Well, because Promise.all() rejects everything even if only one of its promises is rejected. That might mean that if one feed doesn’t behave the way I’d expect it to, my entire page would be blank when I grab my hot beverage to read the news in the morning. I do not want to start my day confronted by an error.

Instead, I’ll opt to use Promise.allSettled(). This method will actually let all promises complete even if one of them fails. In our case, this means any feed that errors will just be ignored, which is perfect.

Let’s add this to the src/pages/index.astro file:

interface FeedItem {
  feed?: string;
  title?: string;
  link?: string;
  date?: Date;
}

const feedItems: FeedItem[] = [];

await Promise.allSettled(
  feedSources.map(async (source) => {
    try {
      const feed = await parser.parseURL(source);
      feed.items.forEach((item) => {
        const date = item.pubDate ? new Date(item.pubDate) : undefined;
        
          feedItems.push({
            feed: feed.title,
            title: item.title,
            link: item.link,
            date,
          });
      });
    } catch (error) {
      console.error(`Error fetching feed from ${source}:`, error);
    }
  })
);

This creates an array (or more) named feedItems. For each URL in the feedSources array we created earlier, the rss-parser retrieves the items and, yes, parses them into JavaScript. Then, we return whatever data we want! We’ll keep it simple for now and only return the following:

• The feed title,
• The title of the feed item,
• The link to the item,
• And the item’s published date.

The next step is to ensure that all items are sorted by date so we’ll truly get the “latest” news. Add this small piece of code to our work:

const sortedFeedItems = feedItems.sort((a, b) => (b.date ?? new Date()).getTime() - (a.date ?? new Date()).getTime());

Oh, and… remember when I said I didn’t want this RSS reader to render anything older than seven days? Let’s tackle that right now since we’re already in this code.

We’ll make a new variable called sevenDaysAgo and assign it a date. We’ll then set that date to seven days ago and use that logic before we add a new item to our feedItems array.

This is what the src/pages/index.astro file should now look like at this point:

---
import Layout from '../layouts/Layout.astro';
import Parser from 'rss-parser';
const parser = new Parser();

const sevenDaysAgo = new Date();
sevenDaysAgo.setDate(sevenDaysAgo.getDate() - 7);

const feedSources = [
  'https://www.smashingmagazine.com/feed/',
  'https://developer.mozilla.org/en-US/blog/rss.xml',
]

interface FeedItem {
  feed?: string;
  title?: string;
  link?: string;
  date?: Date;
}

const feedItems: FeedItem[] = [];

await Promise.allSettled(
  feedSources.map(async (source) => {
    try {
      const feed = await parser.parseURL(source);
      feed.items.forEach((item) => {
        const date = item.pubDate ? new Date(item.pubDate) : undefined;
        if (date && date >= sevenDaysAgo) {
          feedItems.push({
            feed: feed.title,
            title: item.title,
            link: item.link,
            date,
          });
        }
      });
    } catch (error) {
      console.error(`Error fetching feed from ${source}:`, error);
    }
  })
);

const sortedFeedItems = feedItems.sort((a, b) => (b.date ?? new Date()).getTime() - (a.date ?? new Date()).getTime());

---


  

  

Rendering XML Data

It’s time to show our news articles on the Astro site! To keep this simple, we’ll format the items in an unordered list rather than some other fancy layout.

All we need to do is update the element in the file with the XML objects sprinkled in for a feed item’s title, URL, and publish date.

  

  {sortedFeedItems.map(item => (
    

      

        {item.title}
        
{item.feed}
        
{item.date}
      
    
  ))}
  

Go ahead and run pnpm start from the terminal. The page should display an unordered list of feed items. Of course, everything is styled at the moment, but luckily for you, you can make it look exactly like you want with CSS!

And remember that there are even more fields available in the XML for each item if you want to display more information. If you run the following snippet in your DevTools console, you’ll see all of the fields you have at your disposal:

feed.items.forEach(item => {}

Scheduling Daily Static Site Builds

We’re nearly done! The feeds are being fetched, and they are returning data back to us in JavaScript for use in our Astro page template. Since feeds are updated whenever new content is published, we need a way to fetch the latest items from it.

We want to avoid doing any of this manually. So, let’s set this site on Netlify to gain access to their scheduled functions that trigger a rebuild and their build hooks that do the building. Again, other services do this, and you’re welcome to roll this work with another provider — I’m just partial to Netlify since I work there. In any case, you can follow Netlify’s documentation for setting up a new site.

Once your site is hosted and live, you are ready to schedule your rebuilds. A build hook gives you a URL to use to trigger the new build, looking something like this:

https://api.netlify.com/build_hooks/your-build-hook-id

Let’s trigger builds every day at midnight. We’ll use Netlify’s scheduled functions. That’s really why I’m using Netlify to host this in the first place. Having them at the ready via the host greatly simplifies things since there’s no server work or complicated configurations to get this going. Set it and forget it!

We’ll install @netlify/functions (instructions) to the project and then create the following file in the project’s root directory: netlify/functions/deploy.ts.

This is what we want to add to that file:

// netlify/functions/deploy.ts

import type { Config } from '@netlify/functions';

const BUILD_HOOK =
  'https://api.netlify.com/build_hooks/your-build-hook-id'; // replace me!

export default async (req: Request) => {
  await fetch(BUILD_HOOK, {
    method: 'POST',
  })
};

export const config: Config = {
  schedule: '0 0 * * *',
};

If you commit your code and push it, your site should re-deploy automatically. From that point on, it follows a schedule that rebuilds the site every day at midnight, ready for you to take your morning brew and catch up on everything that you think is important.

(gg, yk)

JavaScript comes with a lot of built-in functions that allow you to carry out so many different operations. One of these built-in functions is the Math.random() method, which generates a random floating-point number that can then be manipulated into integers.

However, if you wish to generate a series of unique random numbers and create more random effects in your code, you will need to come up with a custom solution for yourself because the Math.random() method on its own cannot do that for you.

In this article, we’re going to be learning how to circumvent this issue and generate a series of unique random numbers using the Set object in JavaScript, which we can then use to create more randomized effects in our code.

Note: This article assumes that you know how to generate random numbers in JavaScript, as well as how to work with sets and arrays.

Generating a Unique Series of Random Numbers

One of the ways to generate a unique series of random numbers in JavaScript is by using Set objects. The reason why we’re making use of sets is because the elements of a set are unique. We can iteratively generate and insert random integers into sets until we get the number of integers we want.

And since sets do not allow duplicate elements, they are going to serve as a filter to remove all of the duplicate numbers that are generated and inserted into them so that we get a set of unique integers.

Here’s how we are going to approach the work:

1. Create a Set object.
2. Define how many random numbers to produce and what range of numbers to use.
3. Generate each random number and immediately insert the numbers into the Set until the Set is filled with a certain number of them.

The following is a quick example of how the code comes together:

function generateRandomNumbers(count, min, max) {
  // 1: Create a `Set` object
  let uniqueNumbers = new Set();
  while (uniqueNumbers.size < count) {
    // 2: Generate each random number
    uniqueNumbers.add(Math.floor(Math.random() * (max - min + 1)) + min);
  }
  // 3: Immediately insert them numbers into the Set...
  return Array.from(uniqueNumbers);
}
// ...set how many numbers to generate from a given range
console.log(generateRandomNumbers(5, 5, 10));

What the code does is create a new Set object and then generate and add the random numbers to the set until our desired number of integers has been included in the set. The reason why we’re returning an array is because they are easier to work with.

One thing to note, however, is that the number of integers you want to generate (represented by count in the code) should be less than the upper limit of your range plus one (represented by max + 1 in the code). Otherwise, the code will run forever. You can add an if statement to the code to ensure that this is always the case:

function generateRandomNumbers(count, min, max) {
  // if statement checks that `count` is less than `max + 1`
  if (count > max + 1) {
    return "count cannot be greater than the upper limit of range";
  } else {
    let uniqueNumbers = new Set();
    while (uniqueNumbers.size < count) {
      uniqueNumbers.add(Math.floor(Math.random() * (max - min + 1)) + min);
    }
    return Array.from(uniqueNumbers);
  }
}
console.log(generateRandomNumbers(5, 5, 10));

Using the Series of Unique Random Numbers as Array Indexes

It is one thing to generate a series of random numbers. It’s another thing to use them.

Being able to use a series of random numbers with arrays unlocks so many possibilities: you can use them in shuffling playlists in a music app, randomly sampling data for analysis, or, as I did, shuffling the tiles in a memory game.

Let’s take the code from the last example and work off of it to return random letters of the alphabet. First, we’ll construct an array of letters:

const englishAlphabets = [
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];

// rest of code

Then we map the letters in the range of numbers:

const englishAlphabets = [
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];

// generateRandomNumbers()

const randomAlphabets = randomIndexes.map((index) => englishAlphabets[index]);

In the original code, the generateRandomNumbers() function is logged to the console. This time, we’ll construct a new variable that calls the function so it can be consumed by randomAlphabets:

const englishAlphabets = [
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];

// generateRandomNumbers()

const randomIndexes = generateRandomNumbers(5, 0, 25);
const randomAlphabets = randomIndexes.map((index) => englishAlphabets[index]);

Now we can log the output to the console like we did before to see the results:

const englishAlphabets = [
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];

// generateRandomNumbers()

const randomIndexes = generateRandomNumbers(5, 0, 25);
const randomAlphabets = randomIndexes.map((index) => englishAlphabets[index]);
console.log(randomAlphabets);

And, when we put the generateRandomNumbers() function definition back in, we get the final code:

const englishAlphabets = [
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];
function generateRandomNumbers(count, min, max) {
  if (count > max + 1) {
    return "count cannot be greater than the upper limit of range";
  } else {
    let uniqueNumbers = new Set();
    while (uniqueNumbers.size  englishAlphabets[index]);
console.log(randomAlphabets);

So, in this example, we created a new array of alphabets by randomly selecting some letters in our englishAlphabets array.

You can pass in a count argument of englishAlphabets.length to the generateRandomNumbers function if you desire to shuffle the elements in the englishAlphabets array instead. This is what I mean:

generateRandomNumbers(englishAlphabets.length, 0, 25);

Wrapping Up

In this article, we’ve discussed how to create randomization in JavaScript by covering how to generate a series of unique random numbers, how to use these random numbers as indexes for arrays, and also some practical applications of randomization.

The best way to learn anything in software development is by consuming content and reinforcing whatever knowledge you’ve gotten from that content by practicing. So, don’t stop here. Run the examples in this tutorial (if you haven’t done so), play around with them, come up with your own unique solutions, and also don’t forget to share your good work. Ciao!

(yk)

Modern JavaScript regular expressions have come a long way compared to what you might be familiar with. Regexes can be an amazing tool for searching and replacing text, but they have a longstanding reputation (perhaps outdated, as I’ll show) for being difficult to write and understand.

This is especially true in JavaScript-land, where regexes languished for many years, comparatively underpowered compared to their more modern counterparts in PCRE, Perl, .NET, Java, Ruby, C++, and Python. Those days are over.

In this article, I’ll recount the history of improvements to JavaScript regexes (spoiler: ES2018 and ES2024 changed the game), show examples of modern regex features in action, introduce you to a lightweight JavaScript library that makes JavaScript stand alongside or surpass other modern regex flavors, and end with a preview of active proposals that will continue to improve regexes in future versions of JavaScript (with some of them already working in your browser today).

The History of Regular Expressions in JavaScript

ECMAScript 3, standardized in 1999, introduced Perl-inspired regular expressions to the JavaScript language. Although it got enough things right to make regexes pretty useful (and mostly compatible with other Perl-inspired flavors), there were some big omissions, even then. And while JavaScript waited 10 years for its next standardized version with ES5, other programming languages and regex implementations added useful new features that made their regexes more powerful and readable.

But that was then.

Did you know that nearly every new version of JavaScript has made at least minor improvements to regular expressions?

Let’s take a look at them.

Don’t worry if it’s hard to understand what some of the following features mean — we’ll look more closely at several of the key features afterward.

• ES5 (2009) fixed unintuitive behavior by creating a new object every time regex literals are evaluated and allowed regex literals to use unescaped forward slashes within character classes (/[/]/).
• ES6/ES2015 added two new regex flags: y (sticky), which made it easier to use regexes in parsers, and u (unicode), which added several significant Unicode-related improvements along with strict errors. It also added the RegExp.prototype.flags getter, support for subclassing RegExp, and the ability to copy a regex while changing its flags.
• ES2018 was the edition that finally made JavaScript regexes pretty good. It added the s (dotAll) flag, lookbehind, named capture, and Unicode properties (via p{...} and P{...}, which require ES6’s flag u). All of these are extremely useful features, as we’ll see.
• ES2020 added the string method matchAll, which we’ll also see more of shortly.
• ES2022 added flag d (hasIndices), which provides start and end indices for matched substrings.
• And finally, ES2024 added flag v (unicodeSets) as an upgrade to ES6’s flag u. The v flag adds a set of multicharacter “properties of strings” to p{...}, multicharacter elements within character classes via p{...} and q{...}, nested character classes, set subtraction [A--B] and intersection [A&&B], and different escaping rules within character classes. It also fixed case-insensitive matching for Unicode properties within negated sets [^...].

As for whether you can safely use these features in your code today, the answer is yes! The latest of these features, flag v, is supported in Node.js 20 and 2023-era browsers. The rest are supported in 2021-era browsers or earlier.

Each edition from ES2019 to ES2023 also added additional Unicode properties that can be used via p{...} and P{...}. And to be a completionist, ES2021 added string method replaceAll — although, when given a regex, the only difference from ES3’s replace is that it throws if not using flag g.

Aside: What Makes a Regex Flavor Good?

With all of these changes, how do JavaScript regular expressions now stack up against other flavors? There are multiple ways to think about this, but here are a few key aspects:

• Performance.
  This is an important aspect but probably not the main one since mature regex implementations are generally pretty fast. JavaScript is strong on regex performance (at least considering V8’s Irregexp engine, used by Node.js, Chromium-based browsers, and even Firefox; and JavaScriptCore, used by Safari), but it uses a backtracking engine that is missing any syntax for backtracking control — a major limitation that makes ReDoS vulnerability more common.
• Support for advanced features that handle common or important use cases.
  Here, JavaScript stepped up its game with ES2018 and ES2024. JavaScript is now best in class for some features like lookbehind (with its infinite-length support) and Unicode properties (with multicharacter “properties of strings,” set subtraction and intersection, and script extensions). These features are either not supported or not as robust in many other flavors.
• Ability to write readable and maintainable patterns.
  Here, native JavaScript has long been the worst of the major flavors since it lacks the x (“extended”) flag that allows insignificant whitespace and comments. Additionally, it lacks regex subroutines and subroutine definition groups (from PCRE and Perl), a powerful set of features that enable writing grammatical regexes that build up complex patterns via composition.

So, it’s a bit of a mixed bag.

JavaScript regexes have become exceptionally powerful, but they’re still missing key features that could make regexes safer, more readable, and more maintainable (all of which hold some people back from using this power).

“

The good news is that all of these holes can be filled by a JavaScript library, which we’ll see later in this article.

Using JavaScript’s Modern Regex Features

Let’s look at a few of the more useful modern regex features that you might be less familiar with. You should know in advance that this is a moderately advanced guide. If you’re relatively new to regex, here are some excellent tutorials you might want to start with:

• RegexLearn and RegexOne are interactive tutorials that include practice problems.
• JavaScript.info’s regular expressions chapter is a detailed and JavaScript-specific guide.
• Demystifying Regular Expressions (video) is an excellent presentation for beginners by Lea Verou at HolyJS 2017.
• Learn Regular Expressions In 20 Minutes (video) is a live syntax walkthrough in a regex tester.

Named Capture

Often, you want to do more than just check whether a regex matches — you want to extract substrings from the match and do something with them in your code. Named capturing groups allow you to do this in a way that makes your regexes and code more readable and self-documenting.

The following example matches a record with two date fields and captures the values:

const record = 'Admitted: 2024-01-01nReleased: 2024-01-03';
const re = /^Admitted: (?d{4}-d{2}-d{2})nReleased: (?d{4}-d{2}-d{2})$/;
const match = record.match(re);
console.log(match.groups);
/* → {
  admitted: '2024-01-01',
  released: '2024-01-03'
} */

Don’t worry — although this regex might be challenging to understand, later, we’ll look at a way to make it much more readable. The key things here are that named capturing groups use the syntax (?...), and their results are stored on the groups object of matches.

You can also use named backreferences to rematch whatever a named capturing group matched via k, and you can use the values within search and replace as follows:

// Change 'FirstName LastName' to 'LastName, FirstName'
const name = 'Shaquille Oatmeal';
name.replace(/(?w+) (?w+)/, '$, $');
// → 'Oatmeal, Shaquille'

For advanced regexers who want to use named backreferences within a replacement callback function, the groups object is provided as the last argument. Here’s a fancy example:

function fahrenheitToCelsius(str) {
  const re = /(?-?d+(.d+)?)Fb/g;
  return str.replace(re, (...args) => {
    const groups = args.at(-1);
    return Math.round((groups.degrees - 32) * 5/9) + 'C';
  });
}
fahrenheitToCelsius('98.6F');
// → '37C'
fahrenheitToCelsius('May 9 high is 40F and low is 21F');
// → 'May 9 high is 4C and low is -6C'

Lookbehind

Lookbehind (introduced in ES2018) is the complement to lookahead, which has always been supported by JavaScript regexes. Lookahead and lookbehind are assertions (similar to ^ for the start of a string or b for word boundaries) that don’t consume any characters as part of the match. Lookbehinds succeed or fail based on whether their subpattern can be found immediately before the current match position.

For example, the following regex uses a lookbehind (?<=...) to match the word “cat” (only the word “cat”) if it’s preceded by “fat ”:

const re = /(?<=fat )cat/g;
'cat, fat cat, brat cat'.replace(re, 'pigeon');
// → 'cat, fat pigeon, brat cat'

You can also use negative lookbehind — written as (?<!...) — to invert the assertion. That would make the regex match any instance of “cat” that’s not preceded by “fat ”.

const re = /(?<!fat )cat/g;
'cat, fat cat, brat cat'.replace(re, 'pigeon');
// → 'pigeon, fat cat, brat pigeon'

JavaScript’s implementation of lookbehind is one of the very best (matched only by .NET). Whereas other regex flavors have inconsistent and complex rules for when and whether they allow variable-length patterns inside lookbehind, JavaScript allows you to look behind for any subpattern.

The matchAll Method

JavaScript’s String.prototype.matchAll was added in ES2020 and makes it easier to operate on regex matches in a loop when you need extended match details. Although other solutions were possible before, matchAll is often easier, and it avoids gotchas, such as the need to guard against infinite loops when looping over the results of regexes that might return zero-length matches.

Since matchAll returns an iterator (rather than an array), it’s easy to use it in a for...of loop.

const re = /(?w)(?w)/g;
for (const match of str.matchAll(re)) {
  const {char1, char2} = match.groups;
  // Print each complete match and matched subpatterns
  console.log(`Matched "${match[0]}" with "${char1}" and "${char2}"`);
}

Note: matchAll requires its regexes to use flag g (global). Also, as with other iterators, you can get all of its results as an array using Array.from or array spreading.

const matches = [...str.matchAll(/./g)];

Unicode Properties

Unicode properties (added in ES2018) give you powerful control over multilingual text, using the syntax p{...} and its negated version P{...}. There are hundreds of different properties you can match, which cover a wide variety of Unicode categories, scripts, script extensions, and binary properties.

Note: For more details, check out the documentation on MDN.

Unicode properties require using the flag u (unicode) or v (unicodeSets).

Flag v

Flag v (unicodeSets) was added in ES2024 and is an upgrade to flag u — you can’t use both at the same time. It’s a best practice to always use one of these flags to avoid silently introducing bugs via the default Unicode-unaware mode. The decision on which to use is fairly straightforward. If you’re okay with only supporting environments with flag v (Node.js 20 and 2023-era browsers), then use flag v; otherwise, use flag u.

Flag v adds support for several new regex features, with the coolest probably being set subtraction and intersection. This allows using A--B (within character classes) to match strings in A but not in B or using A&&B to match strings in both A and B. For example:

// Matches all Greek symbols except the letter 'π'
/[p{Script_Extensions=Greek}--π]/v

// Matches only Greek letters
/[p{Script_Extensions=Greek}&&p{Letter}]/v

For more details about flag v, including its other new features, check out this explainer from the Google Chrome team.

A Word on Matching Emoji

Emoji are 🤩🔥😎👌, but how emoji get encoded in text is complicated. If you’re trying to match them with a regex, it’s important to be aware that a single emoji can be composed of one or many individual Unicode code points. Many people (and libraries!) who roll their own emoji regexes miss this point (or implement it poorly) and end up with bugs.

The following details for the emoji “👩🏻‍🏫” (Woman Teacher: Light Skin Tone) show just how complicated emoji can be:

// Code unit length
'👩🏻‍🏫'.length;
// → 7
// Each astral code point (above uFFFF) is divided into high and low surrogates

// Code point length
[...'👩🏻‍🏫'].length;
// → 4
// These four code points are: u{1F469} u{1F3FB} u{200D} u{1F3EB}
// u{1F469} combined with u{1F3FB} is '👩🏻'
// u{200D} is a Zero-Width Joiner
// u{1F3EB} is '🏫'

// Grapheme cluster length (user-perceived characters)
[...new Intl.Segmenter().segment('👩🏻‍🏫')].length;
// → 1

Fortunately, JavaScript added an easy way to match any individual, complete emoji via p{RGI_Emoji}. Since this is a fancy “property of strings” that can match more than one code point at a time, it requires ES2024’s flag v.

If you want to match emojis in environments without v support, check out the excellent libraries emoji-regex and emoji-regex-xs.

Making Your Regexes More Readable, Maintainable, and Resilient

Despite the improvements to regex features over the years, native JavaScript regexes of sufficient complexity can still be outrageously hard to read and maintain.

Regular Expressions are SO EASY!!!! pic.twitter.com/q4GSpbJRbZ

— Garabato Kid (@garabatokid) July 5, 2019

ES2018’s named capture was a great addition that made regexes more self-documenting, and ES6’s String.raw tag allows you to avoid escaping all your backslashes when using the RegExp constructor. But for the most part, that’s it in terms of readability.

However, there’s a lightweight and high-performance JavaScript library named regex (by yours truly) that makes regexes dramatically more readable. It does this by adding key missing features from Perl-Compatible Regular Expressions (PCRE) and outputting native JavaScript regexes. You can also use it as a Babel plugin, which means that regex calls are transpiled at build time, so you get a better developer experience without users paying any runtime cost.

PCRE is a popular C library used by PHP for its regex support, and it’s available in countless other programming languages and tools.

Let’s briefly look at some of the ways the regex library, which provides a template tag named regex, can help you write complex regexes that are actually understandable and maintainable by mortals. Note that all of the new syntax described below works identically in PCRE.

Insignificant Whitespace and Comments

By default, regex allows you to freely add whitespace and line comments (starting with #) to your regexes for readability.

import {regex} from 'regex';
const date = regex`
  # Match a date in YYYY-MM-DD format
  (?  d{4}) - # Year part
  (? d{2}) - # Month part
  (?   d{2})   # Day part
`;

This is equivalent to using PCRE’s xx flag.

Subroutines and Subroutine Definition Groups

Subroutines are written as g (where name refers to a named group), and they treat the referenced group as an independent subpattern that they try to match at the current position. This enables subpattern composition and reuse, which improves readability and maintainability.

For example, the following regex matches an IPv4 address such as “192.168.12.123”:

import {regex} from 'regex';
const ipv4 = regex`b
  (? 25[0-5] | 2[0-4]d | 1dd | [1-9]?d)
  # Match the remaining 3 dot-separated bytes
  (. g){3}
b`;

You can take this even further by defining subpatterns for use by reference only via subroutine definition groups. Here’s an example that improves the regex for admittance records that we saw earlier in this article:

const record = 'Admitted: 2024-01-01nReleased: 2024-01-03';
const re = regex`
  ^ Admitted: (? g) n
    Released: (? g) $

  (?(DEFINE)
    (?  g-g-g)
    (?  d{4})
    (? d{2})
    (?   d{2})
  )
`;
const match = record.match(re);
console.log(match.groups);
/* → {
  admitted: '2024-01-01',
  released: '2024-01-03'
} */

A Modern Regex Baseline

regex includes the v flag by default, so you never forget to turn it on. And in environments without native v, it automatically switches to flag u while applying v’s escaping rules, so your regexes are forward and backward-compatible.

It also implicitly enables the emulated flags x (insignificant whitespace and comments) and n (“named capture only” mode) by default, so you don’t have to continually opt into their superior modes. And since it’s a raw string template tag, you don’t have to escape your backslashes like with the RegExp constructor.

Atomic Groups and Possessive Quantifiers Can Prevent Catastrophic Backtracking

Atomic groups and possessive quantifiers are another powerful set of features added by the regex library. Although they’re primarily about performance and resilience against catastrophic backtracking (also known as ReDoS or “regular expression denial of service,” a serious issue where certain regexes can take forever when searching particular, not-quite-matching strings), they can also help with readability by allowing you to write simpler patterns.

Note: You can learn more in the regex documentation.

What’s Next? Upcoming JavaScript Regex Improvements

There are a variety of active proposals for improving regexes in JavaScript. Below, we’ll look at the three that are well on their way to being included in future editions of the language.

Duplicate Named Capturing Groups

This is a Stage 3 (nearly finalized) proposal. Even better is that, as of recently, it works in all major browsers.

When named capturing was first introduced, it required that all (?...) captures use unique names. However, there are cases when you have multiple alternate paths through a regex, and it would simplify your code to reuse the same group names in each alternative.

For example:

/(?d{4})-dd|dd-(?d{4})/

This proposal enables exactly this, preventing a “duplicate capture group name” error with this example. Note that names must still be unique within each alternative path.

Pattern Modifiers (aka Flag Groups)

This is another Stage 3 proposal. It’s already supported in Chrome/Edge 125 and Opera 111, and it’s coming soon for Firefox. No word yet on Safari.

Pattern modifiers use (?ims:...), (?-ims:...), or (?im-s:...) to turn the flags i, m, and s on or off for only certain parts of a regex.

For example:

/hello-(?i:world)/
// Matches 'hello-WORLD' but not 'HELLO-WORLD'

Escape Regex Special Characters with RegExp.escape

This proposal recently reached Stage 3 and has been a long time coming. It isn’t yet supported in any major browsers. The proposal does what it says on the tin, providing the function RegExp.escape(str), which returns the string with all regex special characters escaped so you can match them literally.

If you need this functionality today, the most widely-used package (with more than 500 million monthly npm downloads) is escape-string-regexp, an ultra-lightweight, single-purpose utility that does minimal escaping. That’s great for most cases, but if you need assurance that your escaped string can safely be used at any arbitrary position within a regex, escape-string-regexp recommends the regex library that we’ve already looked at in this article. The regex library uses interpolation to escape embedded strings in a context-aware way.

Conclusion

So there you have it: the past, present, and future of JavaScript regular expressions.

If you want to journey even deeper into the lands of regex, check out Awesome Regex for a list of the best regex testers, tutorials, libraries, and other resources. And for a fun regex crossword puzzle, try your hand at regexle.

May your parsing be prosperous and your regexes be readable.

(gg, yk)

This article is sponsored by Hygraph

Internationalization, often abbreviated as i18n, is the process of designing and developing software applications in a way that they can be easily adapted to various spoken languages like English, German, French, and more without requiring substantial changes to the codebase. It involves moving away from hardcoded strings and techniques for translating text, formatting dates and numbers, and handling different character encodings, among other tasks.

Internationalization can give users the choice to access a given website or application in their native language, which can have a positive impression on them, making it crucial for reaching a global audience.

What We’re Making

In this tutorial, we’re making a website that puts these i18n pieces together using a combination of libraries and a UI framework. You’ll want to have intermediate proficiency with JavaScript, Vue, and Nuxt to follow along. Throughout this article, we will learn by examples and incrementally build a multilingual Nuxt website. Together, we will learn how to provide i18n support for different languages, lazy-load locale messages, and switch locale on runtime.

After that, we will explore features like interpolation, pluralization, and date/time translations.

And finally, we will fetch dynamic localized content from an API server using Hygraph as our API server to get localized content. If you do not have a Hygraph account please create one for free before jumping in.

As a final detail, we will use Vuetify as our UI framework, but please feel free to use another framework if you want. The final code for what we’re building is published in a GitHub repository for reference. And finally, you can also take a look at the final result in a live demo.

The nuxt-i18n Library

nuxt-i18n is a library for implementing internationalization in Nuxt.js applications, and it’s what we will be using in this tutorial. The library is built on top of Vue I18n, which, again, is the de facto standard library for implementing i18n in Vue applications.

What makes nuxt-i18n ideal for our work is that it provides the comprehensive set of features included in Vue I18n while adding more functionalities that are specific to Nuxt, like lazy loading locale messages, route generation and redirection for different locales, SEO metadata per locale, locale-specific domains, and more.

Initial Setup

Start a new Nuxt.js project and set it up with a UI framework of your choice. Again, I will be using Vue to establish the interface for this tutorial.

Let us add a basic layout for our website and set up some sample Vue templates.

First, a “Blog” page:

  

    
      
        Home
      
      
        This is the home page description
      
    
  

Next, an “About” page:

  

    
      
        About
      
      
        This is the about page description
      
    
  

This gives us a bit of a boilerplate that we can integrate our i18n work into.

Translating Plain Text

The page templates look good, but notice how the text is hardcoded. As far as i18n goes, hardcoded content is difficult to translate into different locales. That is where the nuxt-i18n library comes in, providing the language-specific strings we need for the Vue components in the templates.

We’ll start by installing the library via the command line:

npx nuxi@latest module add i18n

Inside the nuxt.config.ts file, we need to ensure that we have @nuxtjs/i18n inside the modules array. We can use the i18n property to provide module-specific configurations.

// nuxt.config.ts
export default defineNuxtConfig({
  // ...
  modules: [
    ...
    "@nuxtjs/i18n",
    // ...
  ],
  i18n: {
    // nuxt-i18n module configurations here
  }
  // ...
});

Since the nuxt-i18n library is built on top of the Vue I18n library, we can utilize its features in our Nuxt application as well. Let us create a new file, i18n.config.ts, which we will use to provide all vue-i18n configurations.

// i18n.config.ts
export default defineI18nConfig(() => ({
  legacy: false,
  locale: "en",
  messages: {
    en: {
      homePage: {
        title: "Home",
        description: "This is the home page description."
      },
      aboutPage: {
        title: "About",
        description: "This is the about page description."
      },
    },
  },
}));

Here, we have specified internationalization configurations, like using the en locale, and added messages for the en locale. These messages can be used inside the markup in the templates we made with the help of a $t function from Vue I18n.

Next, we need to link the i18n.config.ts configurations in our Nuxt config file.

// nuxt.config.ts
export default defineNuxtConfig({
  ...
  i18n: {
    vueI18n: "./i18n.config.ts"
  }
  ...
});

Now, we can use the $t function in our components — as shown below — to parse strings from our internationalization configurations.

Note: There’s no need to import $t since we have Nuxt’s default auto-import functionality.

  

    
      
        {{ $t("homePage.title") }}
      
      
        {{ $t("homePage.description") }}
      
    
  

Lazy Loading Translations

We have the title and description served from the configurations. Next, we can add more languages to the same config. For example, here’s how we can establish translations for English (en), French (fr) and Spanish (es):

// i18n.config.ts
export default defineI18nConfig(() => ({
  legacy: false,
  locale: "en",
  messages: {
    en: {
      // English
    },
    fr: {
      // French
    },
    es: {
      // Spanish
    }
  },
}));

For a production website with a lot of content that needs translating, it would be unwise to bundle all of the messages from different locales in the main bundle. Instead, we should use the nuxt-i18 lazy loading feature asynchronously load only the required language rather than all of them at once. Also, having messages for all locales in a single configuration file can become difficult to manage over time, and breaking them up like this makes things easier to find.

Let’s set up the lazy loading feature in nuxt.config.ts:

// etc.
  i18n: {
    vueI18n: "./i18n.config.ts",
    lazy: true,
    langDir: "locales",
    locales: [
      {
        code: "en",
        file: "en.json",
        name: "English",
      },
      {
        code: "es",
        file: "es.json",
        name: "Spanish",
      },
      {
        code: "fr",
        file: "fr.json",
        name: "French",
      },
    ],
    defaultLocale: "en",
    strategy: "no_prefix",
  },

// etc.

This enables lazy loading and specifies the locales directory that will contain our locale files. The locales array configuration specifies from which files Nuxt.js should pick up messages for a specific language.

Now, we can create individual files for each language. I’ll drop all three of them right here:

// locales/en.json
{
  "homePage": {
    "title": "Home",
    "description": "This is the home page description."
  },
  "aboutPage": {
    "title": "About",
    "description": "This is the about page description."
  },
  "selectLocale": {
    "label": "Select Locale"
  },
  "navbar": {
    "homeButton": "Home",
    "aboutButton": "About"
  }
}

// locales/fr.json
{
  "homePage": {
    "title": "Bienvenue sur la page d'accueil",
    "description": "Ceci est la description de la page d'accueil."
  },
  "aboutPage": {
    "title": "À propos de nous",
    "description": "Ceci est la description de la page à propos de nous."
  },
  "selectLocale": {
    "label": "Sélectionner la langue"
  },
  "navbar": {
    "homeButton": "Accueil",
    "aboutButton": "À propos"
  }
}

// locales/es.json
{
  "homePage": {
    "title": "Bienvenido a la página de inicio",
    "description": "Esta es la descripción de la página de inicio."
  },
  "aboutPage": {
    "title": "Sobre nosotros",
    "description": "Esta es la descripción de la página sobre nosotros."
  },
  "selectLocale": {
    "label": "Seleccione el idioma"
  },
  "navbar": {
    "homeButton": "Inicio",
    "aboutButton": "Acerca de"
  }
}

We have set up lazy loading, added multiple languages to our application, and moved our locale messages to separate files. The user gets the right locale for the right message, and the locale messages are kept in a maintainable manner inside the code base.

Switching Between Languages

We have different locales, but to see them in action, we will build a component that can be used to switch between the available locales.

const { locale, locales, setLocale } = useI18n();

const language = computed({
  get: () => locale.value,
  set: (value) => setLocale(value),
});



  

This component uses the useI18n hook provided by the Vue I18n library and a computed property language to get and set the global locale from a input. To make this even more like a real-world website, we’ll include a small navigation bar that links up all of the website’s pages.

  
    

      
        {{ $t("navbar.homeButton") }}
      
      
        {{ $t("navbar.aboutButton") }}
      
    
    
    

      
    
  

That’s it! Now, we can switch between languages on the fly.

We have a basic layout, but I thought we’d take this a step further and build a playground page we can use to explore more i18n features that are pretty useful when building a multilingual website.

Interpolation and Pluralization

Interpolation and pluralization are internationalization techniques for handling dynamic content and grammatical variations across different languages. Interpolation allows developers to insert dynamic variables or expressions into translated strings. Pluralization addresses the complexities of plural forms in languages by selecting the appropriate grammatical form based on numeric values. With the help of interpolation and pluralization, we can create more natural and accurate translations.

To use pluralization in our Nuxt app, we’ll first add a configuration to the English locale file.

// locales/en.json
{
  // etc.
  "playgroundPage": {
    "pluralization": {
      "title": "Pluralization",
      "apple": "No Apple | One Apple | {count} Apples",
      "addApple": "Add"
    }
  }
  // etc.
}

The pluralization configuration set up for the key apple defines an output — No Apple — if a count of 0 is passed to it, a second output — One Apple — if a count of 1 is passed, and a third — 2 Apples, 3 Apples, and so on — if the count passed in is greater than 1.

Here is how we can use it in your component: Whenever you click on the add button, you will see pluralization in action, changing the strings.

let appleCount = ref(0);
const addApple = () => {
  appleCount.value += 1;
};


  
    
    
      
        {{ $t("playgroundPage.pluralization.title") }}
      

      
        {{ $t("playgroundPage.pluralization.apple", { count: appleCount }) }}
      
      
        {{ $t("playgroundPage.pluralization.addApple") }}
      
    
  

To use interpolation in our Nuxt app, first, add a configuration in the English locale file:

// locales/en.json
{
  ...
  "playgroundPage": {
    ... 
    "interpolation": {
      "title": "Interpolation",
      "sayHello": "Hello, {name}",
      "hobby": "My favourite hobby is {0}.",
      "email": "You can reach out to me at {account}{'@'}{domain}.com"
    },
    // etc. 
  }
  // etc.
}

The message for sayHello expects an object passed to it having a key name when invoked — a process known as named interpolation.

The message hobby expects an array to be passed to it and will pick up the 0^th element, which is known as list interpolation.

The message email expects an object with keys account, and domain and joins both with a literal string "@". This is known as literal interpolation.

Below is an example of how to use it in the Vue components:

  
    
    
      
        {{ $t("playgroundPage.interpolation.title") }}
      
      
        

          {{
            $t("playgroundPage.interpolation.sayHello", {
              name: "Jane",
            })
          }}
        
        

          {{
            $t("playgroundPage.interpolation.hobby", ["Football", "Cricket"])
          }}
        
        

          {{
            $t("playgroundPage.interpolation.email", {
              account: "johndoe",
              domain: "hygraph",
            })
          }}
        
      
    
  

Date & Time Translations

Translating dates and times involves translating date and time formats according to the conventions of different locales. We can use Vue I18n’s features for formatting date strings, handling time zones, and translating day and month names for managing date time translations. We can give the configuration for the same using the datetimeFormats key inside the vue-i18n config object.

// i18n.config.ts
export default defineI18nConfig(() => ({
  fallbackLocale: "en",
  datetimeFormats: {
    en: {
      short: {
        year: "numeric",
        month: "short",
        day: "numeric",
      },
      long: {
        year: "numeric",
        month: "short",
        day: "numeric",
        weekday: "short",
        hour: "numeric",
        minute: "numeric",
        hour12: false,
      },
    },
    fr: {
      short: {
        year: "numeric",
        month: "short",
        day: "numeric",
      },
      long: {
        year: "numeric",
        month: "short",
        day: "numeric",
        weekday: "long",
        hour: "numeric",
        minute: "numeric",
        hour12: true,
      },
    },
    es: {
      short: {
        year: "numeric",
        month: "short",
        day: "numeric",
      },
      long: {
        year: "2-digit",
        month: "short",
        day: "numeric",
        weekday: "long",
        hour: "numeric",
        minute: "numeric",
        hour12: true,
      },
    },
  },
}));

Here, we have set up short and long formats for all three languages. If you are coding along, you will be able to see available configurations for fields, like month and year, thanks to TypeScript and Intellisense features provided by your code editor. To display the translated dates and times in components, we should use the $d function and pass the format to it.

  
    
    
      
        {{ $t("playgroundPage.dateTime.title") }}
      
      
        
Short: {{ (new Date(), $d(new Date(), "short")) }}
        
Long: {{ (new Date(), $d(new Date(), "long")) }}
      
    
  

Localization On the Hygraph Side

We saw how to implement localization with static content. Now, we’ll attempt to understand how to fetch dynamic localized content in Nuxt.

We can build a blog page in our Nuxt App that fetches data from a server. The server API should accept a locale and return data in that specific locale.

Hygraph has a flexible localization API that allows you to publish and query localized content. If you haven’t created a free Hygraph account yet, you can do that on the Hygraph website to continue following along.

Go to Project Settings → Locales and add locales for the API.

We have added two locales: English and French. Now we need aq localized_post model in our schema that only two fields: title and body. Ensure to make these “Localized” fields while creating them.

Add permissions to consume the localized content, go to Project settings → Access → API Access → Public Content API, and assign Read permissions to the localized_post model.

Now, we can go to the Hygrapgh API playground and add some localized data to the database with the help of GraphQL mutations. To limit the scope of this example, I am simply adding data from the Hygraph API playground. In an ideal world, a create/update mutation would be triggered from the front end after receiving user input.

Run this mutation in the Hygraph API playground:

mutation createLocalizedPost {
  createLocalizedPost(
    data: {
      title: "A Journey Through the Alps", 
      body: "Exploring the majestic mountains of the Alps offers a thrilling experience. The stunning landscapes, diverse wildlife, and pristine environment make it a perfect destination for nature lovers.", 
      localizations: {
        create: [
          {locale: fr, data: {title: "Un voyage à travers les Alpes", body: "Explorer les majestueuses montagnes des Alpes offre une expérience palpitante. Les paysages époustouflants, la faune diversifiée et l'environnement immaculé en font une destination parfaite pour les amoureux de la nature."}}
        ]
      }
    }
  ) {
    id
  }
}

The mutation above creates a post with the en locale and includes a fr version of the same post. Feel free to add more data to your model if you want to see things work from a broader set of data.

Putting Things Together

Now that we have Hygraph API content ready for consumption let’s take a moment to understand how it’s consumed inside the Nuxt app.

To do this, we’ll install nuxt-graphql-client to serve as the app’s GraphQL client. This is a minimal GraphQL client for performing GraphQL operations without having to worry about complex configurations, code generation, typing, and other setup tasks.

npx nuxi@latest module add graphql-client

// nuxt.config.ts
export default defineNuxtConfig({
  modules: [
    // ...
    "nuxt-graphql-client"
    // ...
  ],
  runtimeConfig: {
    public: {
      GQL_HOST: 'ADD_YOUR_GQL_HOST_URL_HERE_OR_IN_.env'
    }
  },
});

Next, let’s add our GraphQL queries in graphql/queries.graphql.

query getPosts($locale: [Locale!]!) {
  localizedPosts(locales: $locale) {
    title
    body
  }
}

The GraphQL client will automatically scan .graphql and .gql files and generate client-side code and typings in the .nuxt/gql folder. All we need to do is stop and restart the Nuxt application. After restarting the app, the GraphQL client will allow us to use a GqlGetPosts function to trigger the query.

Now, we will build the Blog page where by querying the Hygraph server and showing the dynamic data.

// pages/blog.vue

  import type { GetPostsQueryVariables } from "#gql";
  import type { PostItem, Locale } from "../types/types";

  const { locale } = useI18n();
  const posts = ref([]);
  const isLoading = ref(false);
  const isError = ref(false);

  const fetchPosts = async (localeValue: Locale) => {
    try {
      isLoading.value = true;
      const variables: GetPostsQueryVariables = {
        locale: [localeValue],
      };
      const data = await GqlGetPosts(variables);
      posts.value = data?.localizedPosts ?? [];
    } catch (err) {
      console.log("Fetch Error, Something went wrong", err);
      isError.value = true;
    } finally {
      isLoading.value = false;
    }
  };

  // Fetch posts on component mount
  onMounted(() => {
    fetchPosts(locale.value as Locale);
  });

  // Watch for locale changes
  watch(locale, (newLocale) => {
    fetchPosts(newLocale as Locale);
  });

This code fetches only the current locale from the useI18n hook and sends it to the fetchPosts function when the Vue component is mounted. The fetchPosts function will pass the locale to the GraphQL query as a variable and obtain localized data from the Hygraph server. We also have a watcher on the locale so that whenever the global locale is changed by the user we make an API call to the server again and fetch posts in that locale.

And, finally, let’s add markup for viewing our fetched data!

  
    Blogs
    

      
    
    

      
Something went wrong while getting blogs please check the logs.
    
    

      

        
          {{ post.title }}
          {{ post.body }}
        
      
    
  

Awesome! If all goes according to plan, then your app should look something like the one in the following video.

Wrapping Up

Check that out — we just made the functionality for translating content for a multilingual website! Now, a user can select a locale from a list of options, and the app fetches content for the selected locale and automatically updates the displayed content.

Did you think that translations would require more difficult steps? It’s pretty amazing that we’re able to cobble together a couple of libraries, hook them up to an API, and wire everything up to render on a page.

Of course, there are other libraries and resources for handling internationalization in a multilingual context. The exact tooling is less the point than it is seeing what pieces are needed to handle dynamic translations and how they come together.

(gg, yk)

A couple of years ago, four JavaScript APIs that landed at the bottom of awareness in the State of JavaScript survey. I took an interest in those APIs because they have so much potential to be useful but don’t get the credit they deserve. Even after a quick search, I was amazed at how many new web APIs have been added to the ECMAScript specification that aren’t getting their dues and with a lack of awareness and browser support in browsers.

That situation can be a “catch-22”:

An API is interesting but lacks awareness due to incomplete support, and there is no immediate need to support it due to low awareness.

“

Most of these APIs are designed to power progressive web apps (PWA) and close the gap between web and native apps. Bear in mind that creating a PWA involves more than just adding a manifest file. Sure, it’s a PWA by definition, but it functions like a bookmark on your home screen in practice. In reality, we need several APIs to achieve a fully native app experience on the web. And the four APIs I’d like to shed light on are part of that PWA puzzle that brings to the web what we once thought was only possible in native apps.

You can see all these APIs in action in this demo as we go along.

1. Screen Orientation API

The Screen Orientation API can be used to sniff out the device’s current orientation. Once we know whether a user is browsing in a portrait or landscape orientation, we can use it to enhance the UX for mobile devices by changing the UI accordingly. We can also use it to lock the screen in a certain position, which is useful for displaying videos and other full-screen elements that benefit from a wider viewport.

Using the global screen object, you can access various properties the screen uses to render a page, including the screen.orientation object. It has two properties:

• type: The current screen orientation. It can be: "portrait-primary", "portrait-secondary", "landscape-primary", or "landscape-secondary".
• angle: The current screen orientation angle. It can be any number from 0 to 360 degrees, but it’s normally set in multiples of 90 degrees (e.g., 0, 90, 180, or 270).

On mobile devices, if the angle is 0 degrees, the type is most often going to evaluate to "portrait" (vertical), but on desktop devices, it is typically "landscape" (horizontal). This makes the type property precise for knowing a device’s true position.

The screen.orientation object also has two methods:

• .lock(): This is an async method that takes a type value as an argument to lock the screen.
• .unlock(): This method unlocks the screen to its default orientation.

And lastly, screen.orientation counts with an "orientationchange" event to know when the orientation has changed.

Browser Support

Finding And Locking Screen Orientation

Let’s code a short demo using the Screen Orientation API to know the device’s orientation and lock it in its current position.

This can be our HTML boilerplate:

  

    Orientation Type: 
    

    Orientation Angle: 
  

  Lock Screen

  Unlock Screen

  Go Full Screen

On the JavaScript side, we inject the screen orientation type and angle properties into our HTML.

let currentOrientationType = document.querySelector(".orientation-type");
let currentOrientationAngle = document.querySelector(".orientation-angle");

currentOrientationType.textContent = screen.orientation.type;
currentOrientationAngle.textContent = screen.orientation.angle;

Now, we can see the device’s orientation and angle properties. On my laptop, they are "landscape-primary" and 0°.

If we listen to the window’s orientationchange event, we can see how the values are updated each time the screen rotates.

window.addEventListener("orientationchange", () => {
  currentOrientationType.textContent = screen.orientation.type;
  currentOrientationAngle.textContent = screen.orientation.angle;
});

To lock the screen, we need to first be in full-screen mode, so we will use another extremely useful feature: the Fullscreen API. Nobody wants a webpage to pop into full-screen mode without their consent, so we need transient activation (i.e., a user click) from a DOM element to work.

The Fullscreen API has two methods:

1. Document.exitFullscreen() is used from the global document object,
2. Element.requestFullscreen() makes the specified element and its descendants go full-screen.

We want the entire page to be full-screen so we can invoke the method from the root element at the document.documentElement object:

const fullscreenButton = document.querySelector(".fullscreen-button");

fullscreenButton.addEventListener("click", async () => {
  // If it is already in full-screen, exit to normal view
  if (document.fullscreenElement) {
    await document.exitFullscreen();
  } else {
    await document.documentElement.requestFullscreen();
  }
});

Next, we can lock the screen in its current orientation:

const lockButton = document.querySelector(".lock-button");

lockButton.addEventListener("click", async () => {
  try {
    await screen.orientation.lock(screen.orientation.type);
  } catch (error) {
    console.error(error);
  }
});

And do the opposite with the unlock button:

const unlockButton = document.querySelector(".unlock-button");

unlockButton.addEventListener("click", () => {
  screen.orientation.unlock();
});

Can’t We Check Orientation With a Media Query?

Yes! We can indeed check page orientation via the orientation media feature in a CSS media query. However, media queries compute the current orientation by checking if the width is “bigger than the height” for landscape or “smaller” for portrait. By contrast,

The Screen Orientation API checks for the screen rendering the page regardless of the viewport dimensions, making it resistant to inconsistencies that may crop up with page resizing.

“

You may have noticed how PWAs like Instagram and X force the screen to be in portrait mode even when the native system orientation is unlocked. It is important to notice that this behavior isn’t achieved through the Screen Orientation API, but by setting the orientation property on the manifest.json file to the desired orientation type.

2. Device Orientation API

Another API I’d like to poke at is the Device Orientation API. It provides access to a device’s gyroscope sensors to read the device’s orientation in space; something used all the time in mobile apps, mainly games. The API makes this happen with a deviceorientation event that triggers each time the device moves. It has the following properties:

• event.alpha: Orientation along the Z-axis, ranging from 0 to 360 degrees.
• event.beta: Orientation along the X-axis, ranging from -180 to 180 degrees.
• event.gamma: Orientation along the Y-axis, ranging from -90 to 90 degrees.

Browser Support

Moving Elements With Your Device

In this case, we will make a 3D cube with CSS that can be rotated with your device! The full instructions I used to make the initial CSS cube are credited to David DeSandro and can be found in his introduction to 3D transforms.

You can see raw full HTML in the demo, but let’s print it here for posterity:

  

    

      
1
      
2
      
3
      
4
      
5
      
6
    
  
  
Device Orientation API
  

    Alpha: 
    

    Beta: 
    

    Gamma: 
  

To keep this brief, I won’t explain the CSS code here. Just keep in mind that it provides the necessary styles for the 3D cube, and it can be rotated through all axes using the CSS rotate() function.

Now, with JavaScript, we listen to the window’s deviceorientation event and access the event orientation data:

const currentAlpha = document.querySelector(".currentAlpha");
const currentBeta = document.querySelector(".currentBeta");
const currentGamma = document.querySelector(".currentGamma");

window.addEventListener("deviceorientation", (event) => {
  currentAlpha.textContent = event.alpha;
  currentBeta.textContent = event.beta;
  currentGamma.textContent = event.gamma;
});

To see how the data changes on a desktop device, we can open Chrome’s DevTools and access the Sensors Panel to emulate a rotating device.

To rotate the cube, we change its CSS transform properties according to the device orientation data:

const currentAlpha = document.querySelector(".currentAlpha");
const currentBeta = document.querySelector(".currentBeta");
const currentGamma = document.querySelector(".currentGamma");

const cube = document.querySelector(".cube");

window.addEventListener("deviceorientation", (event) => {
  currentAlpha.textContent = event.alpha;
  currentBeta.textContent = event.beta;
  currentGamma.textContent = event.gamma;

  cube.style.transform = `rotateX(${event.beta}deg) rotateY(${event.gamma}deg) rotateZ(${event.alpha}deg)`;
});

This is the result:

3. Vibration API

Let’s turn our attention to the Vibration API, which, unsurprisingly, allows access to a device’s vibrating mechanism. This comes in handy when we need to alert users with in-app notifications, like when a process is finished or a message is received. That said, we have to use it sparingly; no one wants their phone blowing up with notifications.

There’s just one method that the Vibration API gives us, and it’s all we need: navigator.vibrate().

vibrate() is available globally from the navigator object and takes an argument for how long a vibration lasts in milliseconds. It can be either a number or an array of numbers representing a patron of vibrations and pauses.

navigator.vibrate(200); // vibrate 200ms
navigator.vibrate([200, 100, 200]); // vibrate 200ms, wait 100, and vibrate 200ms.

Browser Support

Vibration API Demo

Let’s make a quick demo where the user inputs how many milliseconds they want their device to vibrate and buttons to start and stop the vibration, starting with the markup:

  
    Milliseconds:
    
  

  Vibrate
  Stop

We’ll add an event listener for a click and invoke the vibrate() method:

const vibrateButton = document.querySelector(".vibrate-button");
const millisecondsInput = document.querySelector("#milliseconds-input");

vibrateButton.addEventListener("click", () => {
  navigator.vibrate(millisecondsInput.value);
});

To stop vibrating, we override the current vibration with a zero-millisecond vibration.

const stopVibrateButton = document.querySelector(".stop-vibrate-button");

stopVibrateButton.addEventListener("click", () => {
  navigator.vibrate(0);
});

4. Contact Picker API

In the past, it used to be that only native apps could connect to a device’s “contacts”. But now we have the fourth and final API I want to look at: the Contact Picker API.

The API grants web apps access to the device’s contact lists. Specifically, we get the contacts.select() async method available through the navigator object, which takes the following two arguments:

• properties: This is an array containing the information we want to fetch from a contact card, e.g., "name", "address", "email", "tel", and "icon".
• options: This is an object that can only contain the multiple boolean property to define whether or not the user can select one or multiple contacts at a time.

Browser Support

I’m afraid that browser support is next to zilch on this one, limited to Chrome Android, Samsung Internet, and Android’s native web browser at the time I’m writing this.

Selecting User’s Contacts

We will make another demo to select and display the user’s contacts on the page. Again, starting with the HTML:

  Get Contacts
  
Contacts:
  

    
  

Then, in JavaScript, we first construct our elements from the DOM and choose which properties we want to pick from the contacts.

const getContactsButton = document.querySelector(".get-contacts");
const contactList = document.querySelector(".contact-list");

const props = ["name", "tel", "icon"];
const options = {multiple: true};

Now, we asynchronously pick the contacts when the user clicks the getContactsButton.

const getContacts = async () => {
  try {
    const contacts = await navigator.contacts.select(props, options);
  } catch (error) {
    console.error(error);
  }
};

getContactsButton.addEventListener("click", getContacts);

Using DOM manipulation, we can then append a list item to each contact and an icon to the contactList element.

const appendContacts = (contacts) => {
  contacts.forEach(({name, tel, icon}) => {
    const contactElement = document.createElement("li");

    contactElement.innerText = `${name}: ${tel}`;
    contactList.appendChild(contactElement);
  });
};

const getContacts = async () => {
  try {
    const contacts = await navigator.contacts.select(props, options);
    appendContacts(contacts);
  } catch (error) {
    console.error(error);
  }
};

getContactsButton.addEventListener("click", getContacts);

Appending an image is a little tricky since we will need to convert it into a URL and append it for each item in the list.

const getIcon = (icon) => {
  if (icon.length > 0) {
    const imageUrl = URL.createObjectURL(icon[0]);
    const imageElement = document.createElement("img");
    imageElement.src = imageUrl;

    return imageElement;
  }
};

const appendContacts = (contacts) => {
  contacts.forEach(({name, tel, icon}) => {
    const contactElement = document.createElement("li");

    contactElement.innerText = `${name}: ${tel}`;
    contactList.appendChild(contactElement);

    const imageElement = getIcon(icon);
    contactElement.appendChild(imageElement);
  });
};

const getContacts = async () => {
  try {
    const contacts = await navigator.contacts.select(props, options);
    appendContacts(contacts);
  } catch (error) {
    console.error(error);
  }
};

getContactsButton.addEventListener("click", getContacts);

And here’s the outcome:

Note: The Contact Picker API will only work if the context is secure, i.e., the page is served over https:// or wss:// URLs.

Conclusion

There we go, four web APIs that I believe would empower us to build more useful and robust PWAs but have slipped under the radar for many of us. This is, of course, due to inconsistent browser support, so I hope this article can bring awareness to new APIs so we have a better chance to see them in future browser updates.

Aren’t they interesting? We saw how much control we have with the orientation of a device and its screen as well as the level of access we get to access a device’s hardware features, i.e. vibration, and information from other apps to use in our own UI.

But as I said much earlier, there’s a sort of infinite loop where a lack of awareness begets a lack of browser support. So, while the four APIs we covered are super interesting, your mileage will inevitably vary when it comes to using them in a production environment. Please tread cautiously and refer to Caniuse for the latest support information, or check for your own devices using WebAPI Check.

(gg, yk)

This article is sponsored by Netlify

In the past, the web ecosystem moved at a very slow pace. Developers would go years without a new language feature or working around a weird browser quirk. This pushed our technical leaders to come up with creative solutions to circumvent the platform’s shortcomings. We invented bundling, polyfills, and transformation steps to make things work everywhere with less of a hassle.

Slowly, we moved towards some sort of consensus on what we need as an ecosystem. We now have TypeScript and Vite as clear preferences—pushing the needle of what it means to build consistent experiences for the web. Application frameworks have built whole ecosystems on top of them: SolidStart, Nuxt, Remix, and Analog are examples of incredible tools built with such primitives. We can say that Vite and TypeScript are tooling primitives that empower the creation of others in diverse ecosystems.

With bundling and transformation needs somewhat defined, it was only natural that framework authors would move their gaze to the next layer they needed to abstract: the server.

Server Primitives

The UnJS folks have been consistently building agnostic tooling that can be reused in different ecosystems. Thanks to them, we now have frameworks and libraries such as H3 (a minimal Node.js server framework built with TypeScript), which enables Nitro (a whole server runtime powered by Vite, and H3), that in its own turn enabled Vinxi (an application bundler and server runtime that abstracts Nitro and Vite).

Nitro is used already by three major frameworks: Nuxt, Analog, and SolidStart. While Vinxi is also used by SolidStart. This means that any platform which supports one of these, will definitely be able to support the others with zero additional effort.

This is not about taking a bigger slice of the cake. But making the cake bigger for everyone.

Frameworks, platforms, developers, and users benefit from it. We bet on our ecosystem together instead of working in silos with our monolithic solutions. Empowering our developer-users to gain transferable skills and truly choose the best tool for the job with less vendor lock-in than ever before.

Serverless Rejoins Conversation

Such initiatives have probably been noticed by serverless platforms like Netlify. With Platform Primitives, frameworks can leverage agnostic solutions for common necessities such as Incremental Static Regeneration (ISR), Image Optimization, and key/value (kv) storage.

As the name implies, Netlify Platform Primitives are a group of abstractions and helpers made available at a platform level for either frameworks or developers to leverage when using their applications. This brings additional functionality simultaneously to every framework. This is a big and powerful shift because, up until now, each framework would have to create its own solutions and backport such strategies to compatibility layers within each platform.

Moreover, developers would have to wait for a feature to first land on a framework and subsequently for support to arrive in their platform of choice. Now, as long as they’re using Netlify, those primitives are available directly without any effort and time put in by the framework authors. This empowers every ecosystem in a single measure.

Serverless means server infrastructure developers don’t need to handle. It’s not a misnomer, but a format of Infrastructure As A Service.

As mentioned before, Netlify Platform Primitives are three different features:

1. Image CDN
   A content delivery network for images. It can handle format transformation and size optimization via URL query strings.
2. Caching
   Basic primitives for their server runtime that help manage the caching directives for browser, server, and CDN runtimes smoothly.
3. Blobs
   A key/value (KV) storage option is automatically available to your project through their SDK.

Let’s take a quick dive into each of these features and explore how they can increase our productivity with a serverless fullstack experience.

Image CDN

Every image in a /public can be served through a Netlify function. This means it’s possible to access it through a /.netlify/images path. So, without adding sharp or any image optimization package to your stack, deploying to Netlify allows us to serve our users with a better format without transforming assets at build-time. In a SolidStart, in a few lines of code, we could have an Image component that transforms other formats to .webp.

import { type JSX } from "solid-js";

const SITE_URL = "https://example.com";

interface Props extends JSX.ImgHTMLAttributes {
  format?: "webp" | "jpeg" | "png" | "avif" | "preserve";
  quality?: number | "preserve";
}

const getQuality = (quality: Props["quality"]) => {
  if (quality === "preserve") return"";
  return `&q=${quality || "75"}`;
};

function getFormat(format: Props["format"]) {
  switch (format) {
    case "preserve":
      return"  ";
    case "jpeg":
      return `&fm=jpeg`;
    case "png":
      return `&fm=png`;
    case "avif":
      return `&fm=avif`;
    case "webp":
    default:
      return `&fm=webp`;
  }
}

export function Image(props: Props) {
  return (
    
  );
}

Notice the above component is even slightly more complex than bare essentials because we’re enforcing some default optimizations. Our getFormat method transforms images to .webp by default. It’s a broadly supported format that’s significantly smaller than the most common and without any loss in quality. Our get quality function reduces the image quality to 75% by default; as a rule of thumb, there isn’t any perceivable loss in quality for large images while still providing a significant size optimization.

• Check our little component at play.
• Source code: SolidStart and Netlify Primitives.

Caching

By default, Netlify caching is quite extensive for your regular artifacts – unless there’s a new deployment or the cache is flushed manually, resources will last for 365 days. However, because server/edge functions are dynamic in nature, there’s no default caching to prevent serving stale content to end-users. This means that if you have one of these functions in production, chances are there’s some caching to be leveraged to reduce processing time (and expenses).

By adding a cache-control header, you already have done 80% of the work in optimizing your resources for best serving users. Some commonly used cache control directives:

{
  "cache-control": "public, max-age=0, stale-while-revalidate=86400"

}

• public: Store in a shared cache.
• max-age=0: resource is immediately stale.
• stale-while-revalidate=86400: if the cache is stale for less than 1 day, return the cached value and revalidate it in the background.

{
  "cache-control": "public, max-age=86400, must-revalidate"

}

• public: Store in a shared cache.
• max-age=86400: resource is fresh for one day.
• must-revalidate: if a request arrives when the resource is already stale, the cache must be revalidated before a response is sent to the user.

Note: For more extensive information about possible compositions of Cache-Control directives, check the mdn entry on Cache-Control.

The cache is a type of key/value storage. So, once our responses are set with proper cache control, platforms have some heuristics to define what the key will be for our resource within the cache storage. The Web Platform has a second very powerful header that can dictate how our cache behaves.

The Vary response header is composed of a list of headers that will affect the validity of the resource (method and the endpoint URL are always considered; no need to add them). This header allows platforms to define other headers defined by location, language, and other patterns that will define for how long a response can be considered fresh.

The Vary response header is a foundational piece of a special header in Netlify Caching Primitive. The Netlify-Vary will take a set of instructions on which parts of the request a key should be based. It is possible to tune a response key not only by the header but also by the value of the header.

• query: vary by the value of some or all request query parameters.
• header: vary by the value of one or more request headers.
• language: vary by the languages from the Accept-Language header.
• country: vary by the country inferred from a GeoIP lookup on the request IP address.
• cookie: vary by the value of one or more request cookie keys.

This header offers strong fine-control over how your resources are cached. Allowing for some creative strategies to optimize how your app will perform for specific users.

Blob Storage

This is a highly-available key/value store, it’s ideal for frequent reads and infrequent writes. They’re automatically available and provisioned for any Netlify Project.

It’s possible to write on a blob from your runtime or push data for a deployment-specific store. For example, this is how an Action Function would register a number of likes in store with SolidStart.

import { getStore } from "@netlify/blobs";
import { action } from "@solidjs/router";

export const upVote = action(async (formData: FormData) => {
  "use server";

  const postId = formData.get("id");
  const postVotes = formData.get("votes");

  if (typeof postId !== "string" || typeof postVotes !== "string") return;

  const store = getStore("posts");
  const voteSum = Number(postVotes) + 1)
    
  await store.set(postId, String(voteSum);

  console.log("done");
  return voteSum
  
});

• Check @netlify/blobs API documentation for more examples and use-cases.

Final Thoughts

With high-quality primitives, we can enable library and framework creators to create thin integration layers and adapters. This way, instead of focusing on how any specific platform operates, it will be possible to focus on the actual user experience and practical use-cases for such features. Monoliths and deeply integrated tooling make sense to build platforms fast with strong vendor lock-in, but that’s not what the community needs. Betting on the web platform is a more sensible and future-friendly way.

Let me know in the comments what your take is about unbiased tooling versus opinionated setups!

(il)