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Use global Iterator.prototype for down-level generators (#59514)

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This commit is contained in:
Ron Buckton
2024-08-08 12:20:59 -04:00
committed by GitHub
parent 3cf708e179
commit 67d0fc13ce
91 changed files with 345 additions and 301 deletions
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6
src/compiler/factory/emitHelpers.ts
View File

@@ -836,7 +836,7 @@ const asyncGeneratorHelper: UnscopedEmitHelper = {
var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var g = generator.apply(thisArg, _arguments || []), i, q = [];
return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -1102,8 +1102,8 @@ const generatorHelper: UnscopedEmitHelper = {
priority: 6,
text: `
var __generator = (this && this.__generator) || function (thisArg, body) {
var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
function verb(n) { return function (v) { return step([n, v]); }; }
function step(op) {
if (f) throw new TypeError("Generator is already executing.");

22
src/testRunner/unittests/evaluation/asyncGenerator.ts
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@@ -83,4 +83,26 @@ describe("unittests:: evaluation:: asyncGeneratorEvaluation", () => {
{ done: true, value: 2 },
]);
});
it("Supports global `AsyncIterator.prototype` if present", () => {
class AsyncIterator {}
const { gen } = evaluator.evaluateTypeScript(
`
export async function * gen() {}
`,
{ target: ts.ScriptTarget.ES5 },
{ AsyncIterator },
);
const g = gen();
assert.instanceOf(g, AsyncIterator);
});
it("Ignores global `AsyncIterator.prototype` if missing", () => {
const { gen } = evaluator.evaluateTypeScript(
`
export async function * gen() {}
`,
{ target: ts.ScriptTarget.ES5 },
{ AsyncIterator: undefined },
);
gen();
});
});

22
src/testRunner/unittests/evaluation/generator.ts
View File

@@ -39,4 +39,26 @@ describe("unittests:: evaluation:: generatorEvaluation", () => {
assert.deepEqual(g.next(), { value: undefined, done: true });
assert.deepEqual(output, []);
});
it("Supports global `Iterator.prototype` if present", () => {
class Iterator {}
const { gen } = evaluator.evaluateTypeScript(
`
export function * gen() {}
`,
{ target: ts.ScriptTarget.ES5 },
{ Iterator },
);
const g = gen();
assert.instanceOf(g, Iterator);
});
it("Ignores global `Iterator.prototype` if missing", () => {
const { gen } = evaluator.evaluateTypeScript(
`
export function * gen() {}
`,
{ target: ts.ScriptTarget.ES5 },
{ Iterator: undefined },
);
gen();
});
});