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82 lines
2.4 KiB
JavaScript
82 lines
2.4 KiB
JavaScript
/**
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* lodash 4.0.1 (Custom Build) <https://lodash.com/>
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* Build: `lodash modularize exports="npm" -o ./`
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* Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
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* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
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* Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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* Available under MIT license <https://lodash.com/license>
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*/
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var keys = require('lodash.keys');
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/**
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* A specialized version of `_.reduce` for arrays without support for
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* iteratee shorthands.
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*
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* @private
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* @param {Array} array The array to iterate over.
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* @param {Function} iteratee The function invoked per iteration.
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* @param {*} [accumulator] The initial value.
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* @param {boolean} [initAccum] Specify using the first element of `array` as the initial value.
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* @returns {*} Returns the accumulated value.
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*/
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function arrayReduce(array, iteratee, accumulator, initAccum) {
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var index = -1,
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length = array.length;
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if (initAccum && length) {
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accumulator = array[++index];
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}
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while (++index < length) {
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accumulator = iteratee(accumulator, array[index], index, array);
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}
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return accumulator;
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}
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/** Used for built-in method references. */
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var objectProto = global.Object.prototype;
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/** Used to check objects for own properties. */
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var hasOwnProperty = objectProto.hasOwnProperty;
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/**
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* Creates an object composed of the inverted keys and values of `object`.
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* If `object` contains duplicate values, subsequent values overwrite property
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* assignments of previous values unless `multiVal` is `true`.
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*
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* @static
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* @memberOf _
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* @category Object
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* @param {Object} object The object to invert.
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* @param {boolean} [multiVal] Allow multiple values per key.
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* @param- {Object} [guard] Enables use as an iteratee for functions like `_.map`.
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* @returns {Object} Returns the new inverted object.
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* @example
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*
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* var object = { 'a': 1, 'b': 2, 'c': 1 };
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*
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* _.invert(object);
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* // => { '1': 'c', '2': 'b' }
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*
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* // with `multiVal`
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* _.invert(object, true);
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* // => { '1': ['a', 'c'], '2': ['b'] }
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*/
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function invert(object, multiVal, guard) {
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return arrayReduce(keys(object), function(result, key) {
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var value = object[key];
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if (multiVal && !guard) {
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if (hasOwnProperty.call(result, value)) {
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result[value].push(key);
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} else {
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result[value] = [key];
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}
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}
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else {
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result[value] = key;
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}
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return result;
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}, {});
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}
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module.exports = invert;
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