69 lines
2.2 KiB
JavaScript
69 lines
2.2 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule Object.es6
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* @polyfill
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* @nolint
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*/
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// WARNING: This is an optimized version that fails on hasOwnProperty checks
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// and non objects. It's not spec-compliant. It's a perf optimization.
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// This is only needed for iOS 8 and current Android JSC.
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Object.assign = function(target, sources) {
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if (__DEV__) {
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if (target == null) {
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throw new TypeError('Object.assign target cannot be null or undefined');
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}
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if (typeof target !== 'object' && typeof target !== 'function') {
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throw new TypeError(
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'In this environment the target of assign MUST be an object. ' +
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'This error is a performance optimization and not spec compliant.'
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);
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}
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}
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for (var nextIndex = 1; nextIndex < arguments.length; nextIndex++) {
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var nextSource = arguments[nextIndex];
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if (nextSource == null) {
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continue;
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}
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if (__DEV__) {
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if (typeof nextSource !== 'object' &&
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typeof nextSource !== 'function') {
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throw new TypeError(
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'In this environment the sources for assign MUST be an object. ' +
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'This error is a performance optimization and not spec compliant.'
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);
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}
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}
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// We don't currently support accessors nor proxies. Therefore this
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// copy cannot throw. If we ever supported this then we must handle
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// exceptions and side-effects.
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for (var key in nextSource) {
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if (__DEV__) {
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var hasOwnProperty = Object.prototype.hasOwnProperty;
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if (!hasOwnProperty.call(nextSource, key)) {
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throw new TypeError(
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'One of the sources for assign has an enumerable key on the ' +
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'prototype chain. Are you trying to assign a prototype property? ' +
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'We don\'t allow it, as this is an edge case that we do not support. ' +
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'This error is a performance optimization and not spec compliant.'
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);
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}
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}
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target[key] = nextSource[key];
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}
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}
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return target;
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};
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