68 lines
1.7 KiB
Plaintext
68 lines
1.7 KiB
Plaintext
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/**
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* Copyright (c) 2013-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @providesModule keyMirrorRecursive
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* @flow weak
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* @typechecks
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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. If the value is an
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* object, the method is run recursively, including the parent key as a suffix.
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* An optional prefix can be provided that will be prepended to each value.
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*
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* For example:
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*
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* var ACTIONS = keyMirror({FOO: null, BAR: { BAZ: null, BOZ: null }}});
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* ACTIONS.BAR.BAZ = 'BAR.BAZ';
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*
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* Input: {key1: null, key2: { nested1: null, nested2: null }}}
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* Output: {key1: key1, key2: { nested1: nested1, nested2: nested2 }}}
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*
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* var CONSTANTS = keyMirror({FOO: {BAR: null}}, 'NameSpace');
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* console.log(CONSTANTS.FOO.BAR); // NameSpace.FOO.BAR
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*/
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function keyMirrorRecursive<T>(obj: T, prefix?: ?string): T {
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return keyMirrorRecursiveInternal(obj, prefix);
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}
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function keyMirrorRecursiveInternal(
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/*object*/obj,
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/*?string*/prefix) /*object*/{
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var ret = {};
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var key;
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invariant(isObject(obj), 'keyMirrorRecursive(...): Argument must be an object.');
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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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var val = obj[key];
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var newPrefix = prefix ? prefix + '.' + key : key;
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if (isObject(val)) {
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val = keyMirrorRecursiveInternal(val, newPrefix);
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} else {
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val = newPrefix;
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}
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ret[key] = val;
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}
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return ret;
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}
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function isObject(obj) /*boolean*/{
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return obj instanceof Object && !Array.isArray(obj);
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}
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module.exports = keyMirrorRecursive;
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