surma
d44f1d9677
Checkpoint before integration and package validation. Assisted-by: SurmAgent:unknown [read] [edit] [bash]
51 lines
1.5 KiB
JavaScript
51 lines
1.5 KiB
JavaScript
import { assert } from "./assert.js";
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function makeAsyncIter(log) {
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let i = 0;
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return { [Symbol.asyncIterator]() { return {
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next() {
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return Promise.resolve(i < 2 ? { value: i++, done: false }
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: { value: undefined, done: true });
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},
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return() { log.returned++; return Promise.resolve({ done: true }); },
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}; } };
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}
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/* normal completion must NOT call return() */
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{
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const log = { returned: 0 };
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for await (const x of makeAsyncIter(log)) {}
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assert(log.returned, 0);
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}
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/* break is an abrupt completion and must call return() */
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{
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const log = { returned: 0 };
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for await (const x of makeAsyncIter(log)) break;
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assert(log.returned, 1);
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}
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/* throw is an abrupt completion and must call return() */
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{
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const log = { returned: 0 };
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try {
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for await (const x of makeAsyncIter(log)) throw new Error("stop");
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} catch (e) {}
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assert(log.returned, 1);
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}
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/* leaving the loop via break must await the result of return() */
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{
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const order = [];
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const it = { [Symbol.asyncIterator]() { let i = 0; return {
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next() { return Promise.resolve({ value: i++, done: false }); },
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return() {
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order.push("return");
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return Promise.resolve().then(() => { order.push("resolved"); return { done: true }; });
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},
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}; } };
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for await (const x of it) break;
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order.push("after");
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assert(order.join(","), "return,resolved,after");
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}
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