41 lines
1.4 KiB
JavaScript
41 lines
1.4 KiB
JavaScript
/**
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* Copyright 2013-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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*/
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'use strict';
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/**
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* Given a `prevElement` and `nextElement`, determines if the existing
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* instance should be updated as opposed to being destroyed or replaced by a new
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* instance. Both arguments are elements. This ensures that this logic can
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* operate on stateless trees without any backing instance.
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*
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* @param {?object} prevElement
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* @param {?object} nextElement
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* @return {boolean} True if the existing instance should be updated.
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* @protected
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*/
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function shouldUpdateReactComponent(prevElement, nextElement) {
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var prevEmpty = prevElement === null || prevElement === false;
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var nextEmpty = nextElement === null || nextElement === false;
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if (prevEmpty || nextEmpty) {
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return prevEmpty === nextEmpty;
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}
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var prevType = typeof prevElement;
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var nextType = typeof nextElement;
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if (prevType === 'string' || prevType === 'number') {
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return nextType === 'string' || nextType === 'number';
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} else {
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return nextType === 'object' && prevElement.type === nextElement.type && prevElement.key === nextElement.key;
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}
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}
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module.exports = shouldUpdateReactComponent; |