24 lines
798 B
JavaScript
24 lines
798 B
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* strict
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*/
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import isPromise from './isPromise';
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/**
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* Similar to Array.prototype.reduce(), however the reducing callback may return
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* a Promise, in which case reduction will continue after each promise resolves.
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*
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* If the callback does not return a Promise, then this function will also not
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* return a Promise.
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*/
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export default function promiseReduce(values, callback, initialValue) {
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return values.reduce(function (previous, value) {
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return isPromise(previous) ? previous.then(function (resolved) {
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return callback(resolved, value);
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}) : callback(previous, value);
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}, initialValue);
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} |