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36 lines
1.2 KiB
36 lines
1.2 KiB
/** |
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* Copyright 2013-2015, 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 onlyChild |
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*/ |
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'use strict'; |
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var ReactElement = require("./ReactElement"); |
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var invariant = require("./invariant"); |
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/** |
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* Returns the first child in a collection of children and verifies that there |
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* is only one child in the collection. The current implementation of this |
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* function assumes that a single child gets passed without a wrapper, but the |
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* purpose of this helper function is to abstract away the particular structure |
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* of children. |
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* |
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* @param {?object} children Child collection structure. |
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* @return {ReactComponent} The first and only `ReactComponent` contained in the |
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* structure. |
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*/ |
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function onlyChild(children) { |
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("production" !== process.env.NODE_ENV ? invariant( |
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ReactElement.isValidElement(children), |
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'onlyChild must be passed a children with exactly one child.' |
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) : invariant(ReactElement.isValidElement(children))); |
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return children; |
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} |
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module.exports = onlyChild;
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