DEV Community

Syntax - Tasty Web Development Treats

Hasty Treat - Seven Interesting JavaScript Proposals - Async Do, JSON Modules, Immutable Array Methods, and More!

In this Hasty Treat, Scott and Wes talk about seven new JavaScript proposals — what they do, where they’re at, and how you might use them.

Deque - Sponsor

Deque’s axe DevTools makes accessibility testing easy and doesn’t require special expertise. Find and fix issues while you code. Get started with a free trial of axe DevTools Pro at deque.com/syntax. No credit card needed.

LogRocket - Sponsor

LogRocket lets you replay what users do on your site, helping you reproduce bugs and fix issues faster. It’s an exception tracker, a session re-player and a performance monitor. Get 14 days free at logrocket.com/syntax.

Show Notes

03:32 - Seven new JavaScript proposals

06:25 - JSON Modules

09:55 - Array Find From Last

11:40 - Async Do

  • https://github.com/tc39/proposal-async-do-expressions
  • Async do will allow you to group together a block of code and mark it as async.
  • No need for an iife
  • Downside to this is that it’s a code block, so if you need to return any values, you’ll need to jump that up a scope level.
Promise.all([ async do { let result = await fetch('thing A'); await result.json(); }, async do { let result = await fetch('thing B'); await result.json(); }, ]).then(([a, b]) => console.log([a, b]));

14:33 - Change Array By Copy

17:48 - Temporal

18:35 - As Patterns

20:47 - Pattern Matching

{props => match (props) { when ({ loading }) { ; } when ({ error }) { ; } when ({ data }) { ; } }} Tweet us your tasty treats!

Episode source