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Diffstat (limited to 'node_modules/react/lib/onlyChild.js')
-rw-r--r-- | node_modules/react/lib/onlyChild.js | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/node_modules/react/lib/onlyChild.js b/node_modules/react/lib/onlyChild.js new file mode 100644 index 000000000..527d6e64a --- /dev/null +++ b/node_modules/react/lib/onlyChild.js @@ -0,0 +1,37 @@ +/** + * Copyright 2013-present, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under the BSD-style license found in the + * LICENSE file in the root directory of this source tree. An additional grant + * of patent rights can be found in the PATENTS file in the same directory. + * + */ +'use strict'; + +var _prodInvariant = require('./reactProdInvariant'); + +var ReactElement = require('./ReactElement'); + +var invariant = require('fbjs/lib/invariant'); + +/** + * Returns the first child in a collection of children and verifies that there + * is only one child in the collection. + * + * See https://facebook.github.io/react/docs/top-level-api.html#react.children.only + * + * The current implementation of this function assumes that a single child gets + * passed without a wrapper, but the purpose of this helper function is to + * abstract away the particular structure of children. + * + * @param {?object} children Child collection structure. + * @return {ReactElement} The first and only `ReactElement` contained in the + * structure. + */ +function onlyChild(children) { + !ReactElement.isValidElement(children) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'React.Children.only expected to receive a single React element child.') : _prodInvariant('143') : void 0; + return children; +} + +module.exports = onlyChild;
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