feat(loader): make preload() / load() await-able (Promise form)#1512
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preload(assets) now returns a Promise<void> that resolves once every asset has loaded (rejects on failure), so you can `await loader.preload` instead of nesting an onload callback. load(asset) called WITHOUT callbacks likewise returns a Promise for a one-off dynamic load. Fully back-compat: the callback forms, loader.onload, and the LOADER_PROGRESS / LOADER_ERROR / LOADER_COMPLETE events are unchanged, and load(asset, onload, onerror) still returns the resource count — the Promise form only kicks in when no callbacks are passed. Implementation: - preload uses load()'s promise form internally (dropped the per-asset new Promise(callback) wrapper); progress (onResourceLoaded) and error (onLoadingError + LOADER_ERROR) are layered via .then/.catch. - completeLoading no longer throws when no callback is set (await without a callback is now valid) and always emits LOADER_COMPLETE. - behavior notes: cached assets now count toward the progress total (loadCount/resourceCount stay balanced); LOADER_COMPLETE fires even with no callback. Tests: callback form (preload cb, load onload, load onerror, count) and promise form (await preload incl. no-callback, await load, both reject paths). Full suite green. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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loader.preload()/loader.load()are nowawait-ableSmall, additive QoL — modern callers expect to
awaitthe loader instead of nesting anonloadcallback.API
await loader.preload(assets)— returns aPromise<void>that resolves once every asset has loaded, and rejects on failure.await loader.load(asset)— the no-callback form returns a Promise for a one-off dynamic load;load(asset, onload, onerror)still returns the resource count.Fully back-compat
The callback forms,
loader.onload, and theLOADER_PROGRESS/LOADER_ERROR/LOADER_COMPLETEevents are unchanged. The Promise form only activates when no callbacks are passed, so every existingpreload(assets, cb)/load(asset, onload, onerror)call behaves exactly as before (same code path, same callback invocation, same count return).Implementation
preloadwas alreadyPromise.all-based internally — it just didn't return the promise. It now does, and it usesload()'s new promise form per-asset (dropping the per-assetnew Promise(callback)wrapper); progress (onResourceLoaded) and error (onLoadingError+LOADER_ERROR) are layered via.then/.catch.completeLoadingno longer throws when no callback is set (so a bareawait preload([...])resolves on success instead of rejecting) and always emitsLOADER_COMPLETE.onLoadingErrorthrows (no retry — retry isloader.reload()), which previously escaped the parser's async error callback; an awaitedpreload/loadnow rejects cleanly.Behavior notes (minor, intentional)
loadCount/resourceCountstay balanced; fresh loads unchanged).LOADER_COMPLETEnow fires even when no callback is provided.Tests
New
callback form (legacy)andpromise form (await)sub-describes covering both forms side-by-side (preload + load success/error/count, await-with-and-without-callback, both reject paths). Full suite green (4286 / 0 failed);pnpm build(eslint + biome + types) clean.CHANGELOG + the
resourceswiki page updated.🤖 Generated with Claude Code