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51 lines
1.3 KiB
51 lines
1.3 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 keyMirror |
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* @typechecks static-only |
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*/ |
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'use strict'; |
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var invariant = require("./invariant"); |
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/** |
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* Constructs an enumeration with keys equal to their value. |
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* |
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* For example: |
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* |
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* var COLORS = keyMirror({blue: null, red: null}); |
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* var myColor = COLORS.blue; |
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* var isColorValid = !!COLORS[myColor]; |
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* |
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* The last line could not be performed if the values of the generated enum were |
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* not equal to their keys. |
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* |
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* Input: {key1: val1, key2: val2} |
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* Output: {key1: key1, key2: key2} |
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* |
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* @param {object} obj |
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* @return {object} |
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*/ |
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var keyMirror = function(obj) { |
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var ret = {}; |
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var key; |
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("production" !== process.env.NODE_ENV ? invariant( |
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obj instanceof Object && !Array.isArray(obj), |
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'keyMirror(...): Argument must be an object.' |
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) : invariant(obj instanceof Object && !Array.isArray(obj))); |
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for (key in obj) { |
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if (!obj.hasOwnProperty(key)) { |
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continue; |
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} |
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ret[key] = key; |
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} |
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return ret; |
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}; |
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module.exports = keyMirror;
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