source: imaps-frontend/node_modules/es-abstract/2018/CreateAsyncFromSyncIterator.js@ d565449

'use strict';

var GetIntrinsic = require('get-intrinsic');

var $SyntaxError = require('es-errors/syntax');
var $TypeError = require('es-errors/type');
var $Promise = GetIntrinsic('%Promise%', true);

var Call = require('./Call');
var CreateIterResultObject = require('./CreateIterResultObject');
var Get = require('./Get');
var GetMethod = require('./GetMethod');
var IteratorComplete = require('./IteratorComplete');
var IteratorNext = require('./IteratorNext');
var IteratorValue = require('./IteratorValue');
var ObjectCreate = require('./ObjectCreate');
var PromiseResolve = require('./PromiseResolve');
var Type = require('./Type');

var isIteratorRecord = require('../helpers/records/iterator-record');

var SLOT = require('internal-slot');

var callBound = require('call-bind/callBound');

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

var AsyncFromSyncIteratorContinuation = function AsyncFromSyncIteratorContinuation(result) {
        if (Type(result) !== 'Object') {
                throw new $TypeError('Assertion failed: Type(O) is not Object');
        }

        if (arguments.length > 1) {
                throw new $TypeError('although AsyncFromSyncIteratorContinuation should take a second argument, it is not used in this implementation');
        }

        if (!$Promise) {
                throw new $SyntaxError('This environment does not support Promises.');
        }

        return new $Promise(function (resolve) {
                var done = IteratorComplete(result); // step 2
                var value = IteratorValue(result); // step 4
                var valueWrapper = PromiseResolve($Promise, value); // step 6

                // eslint-disable-next-line no-shadow
                var onFulfilled = function (value) { // steps 8-9
                        return CreateIterResultObject(value, done); // step 8.a
                };
                resolve($then(valueWrapper, onFulfilled)); // step 11
        }); // step 12
};

var $AsyncFromSyncIteratorPrototype = GetIntrinsic('%AsyncFromSyncIteratorPrototype%', true) || {
        next: function next(value) {
                if (!$Promise) {
                        throw new $SyntaxError('This environment does not support Promises.');
                }

                var O = this; // step 1

                SLOT.assert(O, '[[SyncIteratorRecord]]'); // step 2

                var argsLength = arguments.length;

                return new $Promise(function (resolve) { // step 3
                        var syncIteratorRecord = SLOT.get(O, '[[SyncIteratorRecord]]'); // step 4
                        var result;
                        if (argsLength > 0) {
                                result = IteratorNext(syncIteratorRecord['[[Iterator]]'], value); // step 5.a
                        } else { // step 6
                                result = IteratorNext(syncIteratorRecord['[[Iterator]]']);// step 6.a
                        }
                        resolve(AsyncFromSyncIteratorContinuation(result)); // step 8
                });
        },
        'return': function () {
                if (!$Promise) {
                        throw new $SyntaxError('This environment does not support Promises.');
                }

                var O = this; // step 1

                SLOT.assert(O, '[[SyncIteratorRecord]]'); // step 2

                var valueIsPresent = arguments.length > 0;
                var value = valueIsPresent ? arguments[0] : void undefined;

                return new $Promise(function (resolve, reject) { // step 3
                        var syncIterator = SLOT.get(O, '[[SyncIteratorRecord]]')['[[Iterator]]']; // step 4
                        var iteratorReturn = GetMethod(syncIterator, 'return'); // step 5

                        if (typeof iteratorReturn === 'undefined') { // step 7
                                var iterResult = CreateIterResultObject(value, true); // step 7.a
                                Call(resolve, undefined, [iterResult]); // step 7.b
                                return;
                        }
                        var result;
                        if (valueIsPresent) { // step 8
                                result = Call(iteratorReturn, syncIterator, [value]); // step 8.a
                        } else { // step 9
                                result = Call(iteratorReturn, syncIterator); // step 9.a
                        }
                        if (Type(result) !== 'Object') { // step 11
                                Call(reject, undefined, [new $TypeError('Iterator `return` method returned a non-object value.')]); // step 11.a
                                return;
                        }

                        resolve(AsyncFromSyncIteratorContinuation(result)); // step 12
                });
        },
        'throw': function () {
                if (!$Promise) {
                        throw new $SyntaxError('This environment does not support Promises.');
                }

                var O = this; // step 1

                SLOT.assert(O, '[[SyncIteratorRecord]]'); // step 2

                var valueIsPresent = arguments.length > 0;
                var value = valueIsPresent ? arguments[0] : void undefined;

                return new $Promise(function (resolve, reject) { // step 3
                        var syncIterator = SLOT.get(O, '[[SyncIteratorRecord]]')['[[Iterator]]']; // step 4

                        var throwMethod = GetMethod(syncIterator, 'throw'); // step 5

                        if (typeof throwMethod === 'undefined') { // step 7
                                Call(reject, undefined, [value]); // step 7.a
                                return;
                        }

                        var result;
                        if (valueIsPresent) { // step 8
                                result = Call(throwMethod, syncIterator, [value]); // step 8.a
                        } else { // step 9
                                result = Call(throwMethod, syncIterator); // step 9.a
                        }
                        if (Type(result) !== 'Object') { // step 11
                                Call(reject, undefined, [new $TypeError('Iterator `throw` method returned a non-object value.')]); // step 11.a
                                return;
                        }

                        resolve(AsyncFromSyncIteratorContinuation(result/* , promiseCapability */)); // step 12
                });
        }
};

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

module.exports = function CreateAsyncFromSyncIterator(syncIteratorRecord) {
        if (!isIteratorRecord(syncIteratorRecord)) {
                throw new $TypeError('Assertion failed: `syncIteratorRecord` is not an Iterator Record');
        }

        // var asyncIterator = ObjectCreate(%AsyncFromSyncIteratorPrototype%, « [[SyncIteratorRecord]] »); // step 1
        var asyncIterator = ObjectCreate($AsyncFromSyncIteratorPrototype);

        SLOT.set(asyncIterator, '[[SyncIteratorRecord]]', syncIteratorRecord); // step 2

        var nextMethod = Get(asyncIterator, 'next'); // step 3

        return { // steps 3-4
                '[[Iterator]]': asyncIterator,
                '[[NextMethod]]': nextMethod,
                '[[Done]]': false
        };
};