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What's new and interesting in JavaScript?

Ben Halpern
A Canadian software developer who thinks he’s funny. He/Him.
・1 min read

JavaScript still moves quickly, what recent developments and releases in the JavaScript ecosystem are worth paying attention to?

Discussion (17)

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nickytonline profile image
Nick Taylor (he/him)

Although not in the language yet, I'm excited to see top-level await, pattern matching as well as the null coalesce operator progress and land in the language. Top-level await is already at stage 3, so that is pretty much a shoe in.

Here's the repos for those interested:

GitHub logo tc39 / proposal-top-level-await

top-level `await` proposal for ECMAScript (stage 3)

ECMAScript proposal: Top-level await

Champion: Myles Borins

Status: Stage 3

Synopsis

Top-level await enables modules to act as big async functions: With top-level await, ECMAScript Modules (ESM) can await resources, causing other modules who import them to wait before they start evaluating their body.

Motivation

Limitations on IIAFEs

With await only available within async functions, a module can include an await in the code that executes at startup by factoring that code into an async function:

// awaiting.mjs
import { process } from "./some-module.mjs"
let output
async function main() {
  const dynamic = await import(computedModuleSpecifier)
  const data = await fetch(url);
  output = process(dynamic.default, data);
}
main();
export { output };

This pattern can also be immediately invoked. You could call this an Immediately Invoked Async Function Expression (IIAFE), as a play on IIFE idiom.

// awaiting.mjs
import

GitHub logo tc39 / proposal-pattern-matching

Pattern matching syntax for ECMAScript

ECMAScript Pattern Matching

Status

Stage: 1

Author: Kat Marchán (npm, @maybekatz)

Champions: Brian Terlson (Microsoft, @bterlson), Sebastian Markbåge (Facebook, @sebmarkbage), Kat Marchán (npm, @maybekatz)

Introduction

This proposal adds a pattern matching expression to the language, based on the existing Destructuring Binding Patterns.

There's many proposals potentially related to this one, and other proposals might mention interaction with this. This file includes casual, example-based discussion of the proposal, and there's also a document describing the core semantics in more formal language, which will be iterated over into the final Spec-ese.

There's also a document including suggestions for other future proposals, which are dependent on this one, but do not directly affect the main behavior of the feature.

This proposal was approved for Stage 1 in the May 2018 TC39 meeting, and slides for that presentation are available.

This proposal draws…

GitHub logo tc39 / proposal-nullish-coalescing

Nullish coalescing proposal x ?? y

Nullish Coalescing for JavaScript

Status

Current Stage:

  • Stage 2

Authors

Overview and motivation

When performing optional property access in a nested structure in conjunction with the optional chaining operator, it is often desired to provide a default value if the result of that property access is null or undefined. At present, a typical way to express this intent in JavaScript is by using the || operator.

const response = {
  settings: {
    nullValue: null
    height: 400
    animationDuration: 0
    headerText: ''
    showSplashScreen: false
  }
};

const undefinedValue = response.settings?.undefinedValue || 'some other default'; // result: 'some other default'
const nullValue = response.settings?.nullValue || 'some other default'; // result:
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kenbellows profile image
Ken Bellows

Oh man I didn't know about the pattern matching proposal! I've been waiting for that exact feature in JS ever since I encountered it in Ruby!!! 😍

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ben profile image
Ben Halpern Author

Interesting!

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copperwall profile image
Chris Opperwall

Oooo I hadn't heard of top-level await before. That's awesome!

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toastking profile image
Matt Del Signore

Pattern matching is one of my favorite features of Standard ML and functional languages. Hopefully they add it to Javacript.

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omrisama profile image
Omri Gabay

Soon?.you?.will?.be?.able?.to?.dig?.through?.objects?.like?.this

github.com/tc39/proposal-optional-...

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jaffparker profile image
Jaff Parker • Edited

While this is useful, it makes the code look undecided 😃 I already see all kinds of good practices that limit the use of this

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lepinekong

svelte: it's more reactive than react and makes programming more inclusive which is my mantra ;)

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guitarino profile image
Kirill Shestakov

I find TypeScript to be exciting right now. It seems that the community became a lot more open to it and even excited about it. It improves the way we interact with 3rd party libraries, with our own code, and makes things better and cleaner. I believe that the next steps for JavaScript / TypeScript will be, like for most other modern languages, to adapt more standards in writing clean code. We may see more things like dependency inversion and separation of concerns.

I find framework wars to be mostly distracting (e.g. recent thing between React and Svelte). They implement and reimplement the wheel, they try to solve the same problem, each time slightly differently, but they don't solve new problems, and, in the end, don't make developers that much more efficient. My hope is that people will realize this and start separating their business logic away from the frameworks rather than putting it in the components, and use frameworks as plug-in if they choose so.

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Prahlad Yeri • Edited

electron is one area where you need to pay attention. Though personally I feel its a crap due to its super bloat and bad performance (a browser container for each app, really?), there is no denying that there are very few players in that niche (seamless OS independence).

Unless Microsoft comes up with a fully platform independent version for WinForms/WPF or Oracle steps up their game with JavaFX, electron has a very super-bright future on desktops.

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Oyetoke Toby

Microfrontends - My twitter feed is filled with people fighting over what micro frontends are and not. Then there's Jamstack, how do we even keep up with technology?

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Ben Halpern Author

React Native still has to essentially compile to what’s available in the native ecosystem right?

As long as the user experience is solid it doesn’t seem like something Google and Apple would be overly concerned about eh?

They’d still be gatekeepers even if the downstream implementation details change.

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agronick profile image
Kyle Agronick

Still waiting for decorators. Looking forward to Vue 3.

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elanandkumar profile image
Anand Kumar

Microfrontends, lerna with tailor and cloud functions

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Jacob Evans

Const thing = const {something: here}

I hope the const on the value is decided to be immut or something else. The immutable keyword for values would be a game changer.