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37 lines
1.2 KiB
37 lines
1.2 KiB
10 years ago
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/**
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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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