DEV Community 👩‍💻👨‍💻

Posted on

Updates from the 90th TC39 meeting

There were several items on the agenda, this post focuses on feature proposals and their progress from the meeting that was held between 6-9th June 2022.

Stage 4:

Array find from last: Proposal for .findLast() and .findLastIndex() methods on array and typed array.

Stage 3:

Symbols as WeakMap keys: Permit Symbols as keys in WeakMaps, entries in WeakSets and WeakRefs, and registered in FinalizationRegistries

Stage 2:

String.dedent: For multi-backtick templates with automatic margin stripping.

Duplicate named capture groups:Allow regex capturing group names to be repeated.

JSON.parse source text access: Extending JSON.parse to expose input source text.

Stage 1:

Faster Promise adoption: Reduce the number of microtask ticks required to adopt the state of a promise

RegExp Atomic Operators: Syntax to regular expressions to control backtracking in certain scenarios by treating certain portions of a pattern as "atomic", where backtracking information specific to that portion of the pattern is discarded when it matches successfully.

More updates:

Array#groupBy is renamed to Array#group, but why? Read on

Tried renaming it on Firefox:



Top comments (0)

Need a better mental model for async/await?

Check out this classic DEV post on the subject.

⭐️🎀 JavaScript Visualized: Promises & Async/Await

async await