// Copyright 2017 Tooru Fujisawa. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- desc: Execution order for yield* with async iterator and next() template: default info: | YieldExpression: yield * AssignmentExpression ... 2. Let value be ? GetValue(exprRef). 3. Let generatorKind be ! GetGeneratorKind(). 4. Let iterator be ? GetIterator(value, generatorKind). 5. Let received be NormalCompletion(undefined). 6. Repeat a. If received.[[Type]] is normal, then i. Let innerResult be ? Invoke(iterator, "next", « received.[[Value]] »). ii. If generatorKind is async, then set innerResult to ? Await(innerResult). ... iv. Let done be ? IteratorComplete(innerResult). v. If done is true, then 1. Let resultValue be ? IteratorValue(innerResult). 2. If generatorKind is async, then set resultValue to ? Await(resultValue). 3. Return resultValue. vi. If generatorKind is async, then let received be AsyncGeneratorYield(? IteratorValue(innerResult)). ... GetIterator ( obj [ , hint ] ) ... 3. If hint is async, a. Set method to ? GetMethod(obj, @@asyncIterator). b. If method is undefined, i. Let syncMethod be ? GetMethod(obj, @@iterator). ii. Let syncIterator be ? Call(syncMethod, obj). iii. Return ? CreateAsyncFromSyncIterator(syncIterator). ... AsyncGeneratorYield ( value ) ... 8. Return ! AsyncGeneratorResolve(generator, value, false). ... flags: [async] features: [Symbol.iterator, async-iteration, Symbol.asyncIterator] ---*/ //- setup var log = []; var obj = { get [Symbol.iterator]() { log.push({ name: "get [Symbol.iterator]" }); }, get [Symbol.asyncIterator]() { log.push({ name: "get [Symbol.asyncIterator]", thisValue: this }); return function() { log.push({ name: "call [Symbol.asyncIterator]", thisValue: this, args: [...arguments] }); var nextCount = 0; return { name: "asyncIterator", get next() { log.push({ name: "get next", thisValue: this }); return function() { log.push({ name: "call next", thisValue: this, args: [...arguments] }); nextCount++; if (nextCount == 1) { return { name: "next-promise-1", get then() { log.push({ name: "get next then (1)", thisValue: this }); return function(resolve) { log.push({ name: "call next then (1)", thisValue: this, args: [...arguments] }); resolve({ name: "next-result-1", get value() { log.push({ name: "get next value (1)", thisValue: this }); return "next-value-1"; }, get done() { log.push({ name: "get next done (1)", thisValue: this }); return false; } }); }; } }; } return { name: "next-promise-2", get then() { log.push({ name: "get next then (2)", thisValue: this }); return function(resolve) { log.push({ name: "call next then (2)", thisValue: this, args: [...arguments] }); resolve({ name: "next-result-2", get value() { log.push({ name: "get next value (2)", thisValue: this }); return "next-value-2"; }, get done() { log.push({ name: "get next done (2)", thisValue: this }); return true; } }); }; } }; }; } }; }; } }; //- body log.push({ name: "before yield*" }); var v = yield* obj; log.push({ name: "after yield*", value: v }); return "return-value"; //- assertions assert.sameValue(log.length, 0, "log.length"); iter.next("next-arg-1").then(v => { assert.sameValue(log[0].name, "before yield*"); assert.sameValue(log[1].name, "get [Symbol.asyncIterator]"); assert.sameValue(log[1].thisValue, obj, "get [Symbol.asyncIterator] thisValue"); assert.sameValue(log[2].name, "call [Symbol.asyncIterator]"); assert.sameValue(log[2].thisValue, obj, "[Symbol.asyncIterator] thisValue"); assert.sameValue(log[2].args.length, 0, "[Symbol.asyncIterator] args.length"); assert.sameValue(log[3].name, "get next"); assert.sameValue(log[3].thisValue.name, "asyncIterator", "get next thisValue"); assert.sameValue(log[4].name, "call next"); assert.sameValue(log[4].thisValue.name, "asyncIterator", "next thisValue"); assert.sameValue(log[4].args.length, 1, "next args.length"); assert.sameValue(log[4].args[0], undefined, "next args[0]"); assert.sameValue(log[5].name, "get next then (1)"); assert.sameValue(log[5].thisValue.name, "next-promise-1", "get next then thisValue"); assert.sameValue(log[6].name, "call next then (1)"); assert.sameValue(log[6].thisValue.name, "next-promise-1", "next then thisValue"); assert.sameValue(log[6].args.length, 2, "next then args.length"); assert.sameValue(typeof log[6].args[0], "function", "next then args[0]"); assert.sameValue(typeof log[6].args[1], "function", "next then args[1]"); assert.sameValue(log[7].name, "get next done (1)"); assert.sameValue(log[7].thisValue.name, "next-result-1", "get next done thisValue"); assert.sameValue(log[8].name, "get next value (1)"); assert.sameValue(log[8].thisValue.name, "next-result-1", "get next value thisValue"); assert.sameValue(v.value, "next-value-1"); assert.sameValue(v.done, false); assert.sameValue(log.length, 9, "log.length"); iter.next("next-arg-2").then(v => { assert.sameValue(log[9].name, "call next"); assert.sameValue(log[9].thisValue.name, "asyncIterator", "next thisValue"); assert.sameValue(log[9].args.length, 1, "next args.length"); assert.sameValue(log[9].args[0], "next-arg-2", "next args[0]"); assert.sameValue(log[10].name, "get next then (2)"); assert.sameValue(log[10].thisValue.name, "next-promise-2", "get next then thisValue"); assert.sameValue(log[11].name, "call next then (2)"); assert.sameValue(log[11].thisValue.name, "next-promise-2", "next then thisValue"); assert.sameValue(log[11].args.length, 2, "next then args.length"); assert.sameValue(typeof log[11].args[0], "function", "next then args[0]"); assert.sameValue(typeof log[11].args[1], "function", "next then args[1]"); assert.sameValue(log[12].name, "get next done (2)"); assert.sameValue(log[12].thisValue.name, "next-result-2", "get next done thisValue"); assert.sameValue(log[13].name, "get next value (2)"); assert.sameValue(log[13].thisValue.name, "next-result-2", "get next value thisValue"); assert.sameValue(log[14].name, "after yield*"); assert.sameValue(log[14].value, "next-value-2"); assert.sameValue(v.value, "return-value"); assert.sameValue(v.done, true); assert.sameValue(log.length, 15, "log.length"); }).then($DONE, $DONE); }).catch($DONE);