66 lines
2.3 KiB
JavaScript
66 lines
2.3 KiB
JavaScript
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'use strict';
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var $ = require('../internals/export');
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var call = require('../internals/function-call');
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var aCallable = require('../internals/a-callable');
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var anObject = require('../internals/an-object');
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var isObject = require('../internals/is-object');
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var getBuiltIn = require('../internals/get-built-in');
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var getIteratorDirect = require('../internals/get-iterator-direct');
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var closeAsyncIteration = require('../internals/async-iterator-close');
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var Promise = getBuiltIn('Promise');
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var $TypeError = TypeError;
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// `AsyncIterator.prototype.reduce` method
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// https://github.com/tc39/proposal-async-iterator-helpers
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$({ target: 'AsyncIterator', proto: true, real: true }, {
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reduce: function reduce(reducer /* , initialValue */) {
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anObject(this);
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aCallable(reducer);
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var record = getIteratorDirect(this);
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var iterator = record.iterator;
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var next = record.next;
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var noInitial = arguments.length < 2;
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var accumulator = noInitial ? undefined : arguments[1];
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var counter = 0;
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return new Promise(function (resolve, reject) {
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var ifAbruptCloseAsyncIterator = function (error) {
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closeAsyncIteration(iterator, reject, error, reject);
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};
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var loop = function () {
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try {
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Promise.resolve(anObject(call(next, iterator))).then(function (step) {
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try {
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if (anObject(step).done) {
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noInitial ? reject($TypeError('Reduce of empty iterator with no initial value')) : resolve(accumulator);
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} else {
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var value = step.value;
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if (noInitial) {
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noInitial = false;
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accumulator = value;
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loop();
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} else try {
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var result = reducer(accumulator, value, counter);
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var handler = function ($result) {
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accumulator = $result;
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loop();
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};
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if (isObject(result)) Promise.resolve(result).then(handler, ifAbruptCloseAsyncIterator);
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else handler(result);
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} catch (error3) { ifAbruptCloseAsyncIterator(error3); }
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}
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counter++;
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} catch (error2) { reject(error2); }
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}, reject);
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} catch (error) { reject(error); }
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};
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loop();
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});
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}
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});
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