Disallow unknown import attributes

Category: JavaScript
Type: No developer-visible change
Status: Enabled by default (Chrome 119)
Intent stage: None

Breaking change: Yes
Enterprise impact: None
Spec maturity: Working draft
Web Platform Tests: Yes

WPT details: https://wpt.fyi/results/html/semantics/scripting-1/the-script-element/import-assertions/unsupported-assertion.html?label=master&label=experimental&aligned=&q=import-assertions

Summary

Throw an error when using unknown keys in import attributes (formerly known as import assertions), such as "import 'x' assert { unknown: 'val' }`, rather than ignoring them. The only accepted attribute remains "type".

Standards & signals

Specification: https://tc39.es/import-attributes
Firefox: No signal
Safari: No signal
Web developers: No signals

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=import-assertions
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+Disallow%20unknown%20import%20attributes
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=Disallow%20unknown%20import%20attributes
Baseline status: https://webstatus.dev/?q=Disallow%20unknown%20import%20attributes

View on chromestatus.com