Syntax - Tasty Web Development Treats

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

Jun 28 '21

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.

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Show Notes

03:32 - Seven new JavaScript proposals

https://github.com/tc39/proposals

06:25 - JSON Modules

https://github.com/tc39/proposal-json-modules
Builds on the import assertions
No named exports
Not executed, to avoid security issues
Not in Node yet

09:55 - Array Find From Last

https://github.com/tc39/proposal-array-find-from-last
The problem: you need to group together async code.The only way to do that right now is to wrap it in a function.

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