Top-level await

Category: JavaScript
Type: New or changed feature
Status: Enabled by default (Chrome 89)
Intent stage: Shipped

Breaking change: No
Enterprise impact: None
Spec maturity: Incubation
Web Platform Tests: No

WPT details: In test262: https://github.com/tc39/test262/tree/master/test/language/module-code/top-level-await Changes to module script timing in WPT in various places. (See the TopLevelAwait virtual WPT suite.)

Summary

Allow the `await` keyword at the top-level within JavaScript modules.

Motivation

Allows more seamless integration of async calls into the module loading process. Today this is accomplished by wrapping modules in async functions, but this pushes complexity into dependent modules and exposes implementation details.

Standards & signals

Specification: https://tc39.es/proposal-top-level-await/
Firefox: Positive
Safari: Positive
Web developers: Positive
Tracking bug: https://bugs.chromium.org/p/v8/issues/detail?id=9344

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=test%2Flanguage%2Fmodule-code%2Ftop-level-await
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+Top-level%20await
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=Top-level%20await
Baseline status: https://webstatus.dev/?q=Top-level%20await

Docs: https://docs.google.com/document/d/15jxKo7kqj0bRHcnSmwjhj1XaWH1AXRDtYPiJHluCSiA/edit

Explainers: https://v8.dev/features/top-level-await https://github.com/tc39/proposal-top-level-await

View on chromestatus.com