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// |reftest| async
// Copyright (C) 2019 André Bargull. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-generator-function-definitions-runtime-semantics-evaluation
description: >
Return resumption value is awaited upon and hence is treated as a thenable.
info: |
14.4.14 Runtime Semantics: Evaluation
YieldExpression : yield AssignmentExpression
...
3. Let value be ? GetValue(exprRef).
4. If generatorKind is async, then return ? AsyncGeneratorYield(value).
...
25.5.3.7 AsyncGeneratorYield ( value )
...
5. Set value to ? Await(value).
...
8. Set the code evaluation state of genContext such that when evaluation is resumed with a
Completion resumptionValue the following steps will be performed:
...
b. Let awaited be Await(resumptionValue.[[Value]]).
...
e. Return Completion { [[Type]]: return, [[Value]]: awaited.[[Value]], [[Target]]: empty }.
...
6.2.3.1 Await
...
2. Let promise be ? PromiseResolve(%Promise%, « value »).
...
25.6.4.5.1 PromiseResolve ( C, x )
...
3. Let promiseCapability be ? NewPromiseCapability(C).
4. Perform ? Call(promiseCapability.[[Resolve]], undefined, « x »).
...
25.6.1.5 NewPromiseCapability ( C )
...
7. Let promise be ? Construct(C, « executor »).
...
25.6.3.1 Promise ( executor )
...
8. Let resolvingFunctions be CreateResolvingFunctions(promise).
...
25.6.1.3 CreateResolvingFunctions ( promise )
...
2. Let stepsResolve be the algorithm steps defined in Promise Resolve Functions (25.6.1.3.2).
3. Let resolve be CreateBuiltinFunction(stepsResolve, « [[Promise]], [[AlreadyResolved]] »).
...
25.6.1.3.2 Promise Resolve Functions
...
9. Let then be Get(resolution, "then").
...
includes: [compareArray.js]
flags: [async]
features: [async-iteration]
---*/
var expected = [
"start",
// `Await(value)` promise resolved.
"tick 1",
// "then" of `resumptionValue.[[Value]]` accessed.
"get then",
// `Await(resumptionValue.[[Value]])` promise resolved.
"tick 2",
];
var actual = [];
async function* f() {
actual.push("start");
yield 123;
actual.push("stop - never reached");
}
Promise.resolve(0)
.then(() => actual.push("tick 1"))
.then(() => actual.push("tick 2"))
.then(() => {
assert.compareArray(actual, expected, "Ticks for return with thenable getter");
}).then($DONE, $DONE);
var it = f();
// Start generator execution.
it.next();
// Stop generator execution.
it.return({
get then() {
actual.push("get then");
}
});
|
