Skip happy-dom registration in browsers

[DmitrySharabin]

Conditionally register happy-dom in Node only so the test entry can also load in a browser. Restructure test/index.js to await happy-dom before importing test modules, avoiding a TLA-vs-sync-sibling race on PropChangeEvent's CustomEvent base.

🤖 Generated with Claude Code

[LeaVerou]

Instead of turning all our imports into async imports, which doesn't scale, we can just import (statically) a file which checks if we have a DOM and if not, dynamic imports happy-dom and does the other stuff. Then all the complexity lives in that file, which is imported normally before other imports in every test that needs it. What am I missing?

[DmitrySharabin]

Tried that first (it was actually our initial shape). The literal version — test/index.js keeps static imports, the conditional await import("@happy-dom/global-registrator") lives inside test/util/happy-dom.js — fails on Node 24 with Failed to execute 'dispatchEvent' on 'EventTarget': parameter 1 is not of type 'Event'. ESM lets sibling modules evaluate while a TLA-holding sibling is paused, so PropChangeEvent (loaded transitively via Prop.js) does extends CustomEvent before happy-dom registers and ends up extending native CustomEvent.

f9e3a29 keeps the spirit of your suggestion: test/index.js is a thin boot wrapper that statically imports happy-dom.js (whose TLA resolves before the body runs), then dynamic-imports test/index-fn.js which holds plain static imports of the test tree. Same index.js/index-fn.js convention as src/.

— answered by Claude (Opus 4.7) on behalf of @DmitrySharabin

[LeaVerou]

The thing is, tests need to be able to run independently, they shouldn't break if not loaded from the root.

Until we find a better solution I'd suggest loading it in every case and just not registering in browser environments. It's wasteful, but at least the wart then lives with that file, rather than infecting the entire testsuite.