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[New] ES2018+: Add CreateAsyncFromSyncIterator #105

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[New] ES2018+: Add CreateAsyncFromSyncIterator #105

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ba475cf
[New] `ES2018+`: Add `CreateAsyncFromSyncIterator`
ExE-Boss Jun 14, 2020
f62b124
Update `expectedMissing`
ExE-Boss Jun 14, 2020
a0eedfa
Move `AsyncFromSyncIteratorPrototype` implementation to `helpers`
ExE-Boss Jun 17, 2020
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4 changes: 3 additions & 1 deletion .gitattributes
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Expand Up @@ -367,10 +367,12 @@
2019/ArrayCreate.js spackled linguist-generated=true
2019/ArraySetLength.js spackled linguist-generated=true
2019/ArraySpeciesCreate.js spackled linguist-generated=true
2019/AsyncFromSyncIteratorContinuation.js spackled linguist-generated=true
2019/Call.js spackled linguist-generated=true
2019/CanonicalNumericIndexString.js spackled linguist-generated=true
2019/CompletePropertyDescriptor.js spackled linguist-generated=true
2019/CopyDataProperties.js spackled linguist-generated=true
2019/CreateAsyncFromSyncIterator.js spackled linguist-generated=true
2019/CreateDataProperty.js spackled linguist-generated=true
2019/CreateDataPropertyOrThrow.js spackled linguist-generated=true
2019/CreateHTML.js spackled linguist-generated=true
Expand Down Expand Up @@ -482,4 +484,4 @@
2019/thisBooleanValue.js spackled linguist-generated=true
2019/thisNumberValue.js spackled linguist-generated=true
2019/thisStringValue.js spackled linguist-generated=true
2019/thisSymbolValue.js spackled linguist-generated=true
2019/thisSymbolValue.js spackled linguist-generated=true
37 changes: 37 additions & 0 deletions 2018/AsyncFromSyncIteratorContinuation.js
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'use strict';

var GetIntrinsic = require('../GetIntrinsic.js');
var callBound = require('../helpers/callBound.js');

var Call = require('./Call.js');
var CreateIterResultObject = require('./CreateIterResultObject.js');
var IteratorComplete = require('./IteratorComplete.js');
var IteratorValue = require('./IteratorValue.js');

var PromiseResolve = require('./PromiseResolve.js');

var $Promise = GetIntrinsic('%Promise%', true);
var PerformPromiseThen = callBound('%Promise.prototype.then%', true);

// https://www.ecma-international.org/ecma-262/9.0/#sec-asyncfromsynciteratorcontinuation

module.exports = function AsyncFromSyncIteratorContinuation(result, promiseCapability) {
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the spec doesn't have the proper assertions here (see tc39/ecma262#2050) but i think we should write a helper and the runtime check here.

try {
var done = IteratorComplete(result);
var value = IteratorValue(result);
var valueWrapper = PromiseResolve($Promise, value);

PerformPromiseThen(
valueWrapper,
function onFulfilled(unwrappedValue) {
Call(promiseCapability['[[Resolve]]'], undefined, [
CreateIterResultObject(unwrappedValue, done)
]);
},
promiseCapability['[[Reject]]']
);
} catch (error) {
Call(promiseCapability['[[Reject]]'], undefined, [error]);
}
return promiseCapability['[[Promise]]'];
};
183 changes: 183 additions & 0 deletions 2018/CreateAsyncFromSyncIterator.js
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'use strict';

var internalSlot = require('internal-slot');
var GetIntrinsic = require('../GetIntrinsic.js');

var AsyncFromSyncIteratorContinuation = require('./AsyncFromSyncIteratorContinuation.js');
var Call = require('./Call.js');
var CreateIterResultObject = require('./CreateIterResultObject.js');
var CreateMethodProperty = require('./CreateMethodProperty.js');
var DefinePropertyOrThrow = require('./DefinePropertyOrThrow.js');
var Get = require('./Get.js');
var GetMethod = require('./GetMethod.js');
var IteratorNext = require('./IteratorNext.js');
var OrdinaryObjectCreate = require('./ObjectCreate.js');
var Type = require('./Type.js');

var $asyncIterator = GetIntrinsic('%Symbol.asyncIterator%', true);
var $toStringTag = GetIntrinsic('%Symbol.toStringTag%', true);
var $TypeError = GetIntrinsic('%TypeError%');

// TODO: Use %AsyncIterator.from% once it's in ECMA-262

var AsyncIteratorPrototype
= GetIntrinsic('%AsyncIteratorPrototype%', true)
|| (function () {
var result = {};
if ($toStringTag) {
DefinePropertyOrThrow(result, $toStringTag, {
'[[Writable]]': false,
'[[Enumerable]]': false,
'[[Configurable]]': true,
'[[Value]]': 'AsyncIterator'
});
}
if ($asyncIterator) {
var method = {
'[Symbol.asyncIterator]': function () {
return this;
}
}['[Symbol.asyncIterator]'];
CreateMethodProperty(result, $asyncIterator, method);
}
return result;
}());

var AsyncFromSyncIteratorPrototype
= GetIntrinsic('%AsyncFromSyncIteratorPrototype%', true)
// eslint-disable-next-line max-lines-per-function
|| (function () {
var $Promise = GetIntrinsic('%Promise%', true);
if (!$Promise) {
return;
}

// eslint-disable-next-line no-shadow
var AsyncFromSyncIteratorPrototype = OrdinaryObjectCreate(AsyncIteratorPrototype);
CreateMethodProperty(AsyncFromSyncIteratorPrototype, 'next', function next(value) {
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Arguably, these function bodies should be wrapped in the callback to new $Promise.

// eslint-disable-next-line no-invalid-this
var O = this;
var promiseCapability = {};
promiseCapability['[[Promise]]'] = new $Promise(function (resolve, reject) {
promiseCapability['[[Resolve]]'] = resolve;
promiseCapability['[[Reject]]'] = reject;
});

if (Type(O) !== 'Object' || !internalSlot.has(O, '[[SyncIteratorRecord]]')) {
Call(promiseCapability['[[Reject]]'], undefined, [
new $TypeError('%AsyncFromSyncIteratorPrototype%.next called on invalid receiver')
]);
return promiseCapability['[[Promise]]'];
}

var result;
try {
var syncIteratorRecord = internalSlot.get(O, '[[SyncIteratorRecord]]');
result = IteratorNext(syncIteratorRecord, value);
} catch (error) {
Call(promiseCapability['[[Reject]]'], undefined, [error]);
return promiseCapability['[[Promise]]'];
}
return AsyncFromSyncIteratorContinuation(result, promiseCapability);
});

CreateMethodProperty(AsyncFromSyncIteratorPrototype, 'return', function (value) {
// eslint-disable-next-line no-invalid-this
var O = this;
var promiseCapability = {};
promiseCapability['[[Promise]]'] = new $Promise(function (resolve, reject) {
promiseCapability['[[Resolve]]'] = resolve;
promiseCapability['[[Reject]]'] = reject;
});

if (Type(O) !== 'Object' || !internalSlot.has(O, '[[SyncIteratorRecord]]')) {
Call(promiseCapability['[[Reject]]'], undefined, [
new $TypeError('%AsyncFromSyncIteratorPrototype%.return called on invalid receiver')
]);
return promiseCapability['[[Promise]]'];
}

var syncIterator = internalSlot.get(O, '[[SyncIteratorRecord]]')['[[SyncIterator]]'];
var result;
try {
var returnMethod = GetMethod(syncIterator, 'return');
if (returnMethod === undefined) {
var iterResult = CreateIterResultObject(value, true);
Call(promiseCapability['[[Resolve]]'], undefined, [iterResult]);
return promiseCapability['[[Promise]]'];
}

result = Call(returnMethod, syncIterator, [value]);
if (Type(result) !== 'Object') {
Call(promiseCapability['[[Reject]]'], undefined, [
new $TypeError('iterator return must return an object')
]);
return promiseCapability['[[Promise]]'];
}
} catch (error) {
Call(promiseCapability['[[Reject]]'], undefined, [error]);
return promiseCapability['[[Promise]]'];
}
return AsyncFromSyncIteratorContinuation(result, promiseCapability);
});

CreateMethodProperty(AsyncFromSyncIteratorPrototype, 'throw', function (value) {
// eslint-disable-next-line no-invalid-this
var O = this;
var promiseCapability = {};
promiseCapability['[[Promise]]'] = new $Promise(function (resolve, reject) {
promiseCapability['[[Resolve]]'] = resolve;
promiseCapability['[[Reject]]'] = reject;
});

if (Type(O) !== 'Object' || !internalSlot.has(O, '[[SyncIteratorRecord]]')) {
Call(promiseCapability['[[Reject]]'], undefined, [
new $TypeError('%AsyncFromSyncIteratorPrototype%.return called on invalid receiver')
]);
return promiseCapability['[[Promise]]'];
}

var syncIterator = internalSlot.get(O, '[[SyncIteratorRecord]]')['[[SyncIterator]]'];
var result;
try {
var throwMethod = GetMethod(syncIterator, 'throw');
if (throwMethod === undefined) {
var iterResult = CreateIterResultObject(value, true);
Call(promiseCapability['[[Reject]]'], undefined, [iterResult]);
return promiseCapability['[[Promise]]'];
}

result = Call(throwMethod, syncIterator, [value]);
if (Type(result) !== 'Object') {
Call(promiseCapability['[[Reject]]'], undefined, [
new $TypeError('iterator throw must return an object')
]);
return promiseCapability['[[Promise]]'];
}
} catch (error) {
Call(promiseCapability['[[Reject]]'], undefined, [error]);
return promiseCapability['[[Promise]]'];
}
return AsyncFromSyncIteratorContinuation(result, promiseCapability);
});

// eslint-disable-next-line consistent-return
return AsyncFromSyncIteratorPrototype;
}());

// https://www.ecma-international.org/ecma-262/9.0/#sec-createasyncfromsynciterator

module.exports = function CreateAsyncFromSyncIterator(syncIteratorRecord) {
if (!AsyncFromSyncIteratorPrototype) {
throw new SyntaxError('This environment does not support Promises.');
}

var asyncIterator = OrdinaryObjectCreate(AsyncFromSyncIteratorPrototype);
internalSlot.set(asyncIterator, '[[SyncIteratorRecord]]', syncIteratorRecord);
var nextMethod = Get(asyncIterator, 'next');
return {
'[[Iterator]]': asyncIterator,
'[[NextMethod]]': nextMethod,
'[[Done]]': false
};
};
37 changes: 37 additions & 0 deletions 2019/AsyncFromSyncIteratorContinuation.js
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@@ -0,0 +1,37 @@
'use strict';

var GetIntrinsic = require('../GetIntrinsic.js');
var callBound = require('../helpers/callBound.js');

var Call = require('./Call.js');
var CreateIterResultObject = require('./CreateIterResultObject.js');
var IteratorComplete = require('./IteratorComplete.js');
var IteratorValue = require('./IteratorValue.js');

var PromiseResolve = require('./PromiseResolve.js');

var $Promise = GetIntrinsic('%Promise%', true);
var PerformPromiseThen = callBound('%Promise.prototype.then%', true);

// https://www.ecma-international.org/ecma-262/9.0/#sec-asyncfromsynciteratorcontinuation

module.exports = function AsyncFromSyncIteratorContinuation(result, promiseCapability) {
try {
var done = IteratorComplete(result);
var value = IteratorValue(result);
var valueWrapper = PromiseResolve($Promise, value);

PerformPromiseThen(
valueWrapper,
function onFulfilled(unwrappedValue) {
Call(promiseCapability['[[Resolve]]'], undefined, [
CreateIterResultObject(unwrappedValue, done)
]);
},
promiseCapability['[[Reject]]']
);
} catch (error) {
Call(promiseCapability['[[Reject]]'], undefined, [error]);
}
return promiseCapability['[[Promise]]'];
};
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