| // Copyright (C) 2019 André Bargull. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| |
| /*--- |
| esid: sec-createasyncfromsynciterator |
| description: > |
| Async-from-Sync Iterator instances are not accessible from user code. |
| info: | |
| 25.1.4.1 CreateAsyncFromSyncIterator ( syncIteratorRecord ) |
| 1. Let asyncIterator be ! ObjectCreate(%AsyncFromSyncIteratorPrototype%, « [[SyncIteratorRecord]] »). |
| 2. Set asyncIterator.[[SyncIteratorRecord]] to syncIteratorRecord. |
| 3. Let nextMethod be ! Get(asyncIterator, "next"). |
| 4. Let iteratorRecord be Record { [[Iterator]]: asyncIterator, [[NextMethod]]: nextMethod, [[Done]]: false }. |
| 5. Return iteratorRecord. |
| |
| 14.4.14 Runtime Semantics: Evaluation |
| YieldExpression : yield * AssignmentExpression |
| 1. Let generatorKind be ! GetGeneratorKind(). |
| ... |
| 4. Let iteratorRecord be ? GetIterator(value, generatorKind). |
| ... |
| |
| 7.4.1 GetIterator ( obj [ , hint [ , method ] ] ) |
| ... |
| 3. If method is not present, then |
| a. If hint is async, then |
| i. Set method to ? GetMethod(obj, @@asyncIterator). |
| ii. If method is undefined, then |
| 1. Let syncMethod be ? GetMethod(obj, @@iterator). |
| 2. Let syncIteratorRecord be ? GetIterator(obj, sync, syncMethod). |
| 3. Return ? CreateAsyncFromSyncIterator(syncIteratorRecord). |
| ... |
| |
| flags: [async] |
| features: [async-iteration] |
| ---*/ |
| |
| var AsyncIteratorPrototype = Object.getPrototypeOf(async function*(){}.constructor.prototype.prototype); |
| |
| Object.defineProperty(AsyncIteratorPrototype, Symbol.iterator, { |
| get() { |
| throw new Error("@@iterator accessed"); |
| } |
| }); |
| |
| Object.defineProperty(AsyncIteratorPrototype, Symbol.asyncIterator, { |
| get() { |
| throw new Error("@@asyncIterator accessed"); |
| } |
| }); |
| |
| async function* g() { |
| yield* []; |
| } |
| g().next().then(() => $DONE(), $DONE); |