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async-iterator-create-proxy.js
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async-iterator-create-proxy.js
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'use strict';
var call = require('../internals/function-call');
var perform = require('../internals/perform');
var anObject = require('../internals/an-object');
var create = require('../internals/object-create');
var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
var defineBuiltIns = require('../internals/define-built-ins');
var wellKnownSymbol = require('../internals/well-known-symbol');
var InternalStateModule = require('../internals/internal-state');
var getBuiltIn = require('../internals/get-built-in');
var getMethod = require('../internals/get-method');
var AsyncIteratorPrototype = require('../internals/async-iterator-prototype');
var Promise = getBuiltIn('Promise');
var ASYNC_ITERATOR_PROXY = 'AsyncIteratorProxy';
var setInternalState = InternalStateModule.set;
var getInternalState = InternalStateModule.getterFor(ASYNC_ITERATOR_PROXY);
var TO_STRING_TAG = wellKnownSymbol('toStringTag');
module.exports = function (nextHandler, IS_ITERATOR) {
var AsyncIteratorProxy = function AsyncIterator(record, state) {
if (state) {
state.iterator = record.iterator;
state.next = record.next;
} else state = record;
state.type = ASYNC_ITERATOR_PROXY;
state.done = false;
setInternalState(this, state);
};
AsyncIteratorProxy.prototype = defineBuiltIns(create(AsyncIteratorPrototype), {
next: function next() {
var that = this;
var result = perform(function () {
var state = getInternalState(that);
return state.done ? { done: true, value: undefined } : anObject(call(nextHandler, state, Promise));
});
return result.error ? Promise.reject(result.value) : Promise.resolve(result.value);
},
'return': function (value) {
var that = this;
return new Promise(function (resolve, reject) {
var state = getInternalState(that);
var iterator = state.iterator;
state.done = true;
var $$return = getMethod(iterator, 'return');
if ($$return === undefined) return resolve({ done: true, value: value });
Promise.resolve(call($$return, iterator, value)).then(function (result) {
anObject(result);
resolve({ done: true, value: value });
}, reject);
});
},
'throw': function (value) {
var that = this;
return new Promise(function (resolve, reject) {
var state = getInternalState(that);
var iterator = state.iterator;
state.done = true;
var $$throw = getMethod(iterator, 'throw');
if ($$throw === undefined) return reject(value);
resolve(call($$throw, iterator, value));
});
}
});
if (!IS_ITERATOR) {
createNonEnumerableProperty(AsyncIteratorProxy.prototype, TO_STRING_TAG, 'Generator');
}
return AsyncIteratorProxy;
};