46 lines
1.5 KiB
JavaScript
46 lines
1.5 KiB
JavaScript
// META: global=window,worker
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'use strict';
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function performMicrotaskCheckpoint() {
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document.createNodeIterator(document, -1, {
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acceptNode() {
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return NodeFilter.FILTER_ACCEPT;
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}
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}).nextNode();
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}
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test(() => {
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// Add a getter for "then" that will incidentally be invoked
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// during promise resolution.
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Object.prototype.__defineGetter__('then', () => {
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// Clean up behind ourselves.
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delete Object.prototype.then;
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// This promise should (like all promises) be resolved
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// asynchronously.
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var executed = false;
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Promise.resolve().then(_ => { executed = true; });
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// This shouldn't run microtasks! They should only run
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// after the fetch is resolved.
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performMicrotaskCheckpoint();
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// The fulfill handler above shouldn't have run yet. If it has run,
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// throw to reject this promise and fail the test.
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assert_false(executed, "shouldn't have run microtasks yet");
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// Otherwise act as if there's no "then" property so the promise
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// fulfills and the test passes.
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return undefined;
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});
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const readable = new ReadableStream({
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pull(c) {
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c.enqueue({});
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}
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}, { highWaterMark: 0 });
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// Create a read request, incidentally resolving a promise with an
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// object value, thereby invoking the getter installed above.
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readable.getReader().read();
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}, "reading from a stream should occur in a microtask scope");
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