1 | var baseIteratee = require('./_baseIteratee'),
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2 | createInverter = require('./_createInverter');
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3 |
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4 | /** Used for built-in method references. */
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5 | var objectProto = Object.prototype;
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6 |
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7 | /** Used to check objects for own properties. */
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8 | var hasOwnProperty = objectProto.hasOwnProperty;
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9 |
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10 | /**
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11 | * Used to resolve the
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12 | * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
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13 | * of values.
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14 | */
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15 | var nativeObjectToString = objectProto.toString;
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16 |
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17 | /**
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18 | * This method is like `_.invert` except that the inverted object is generated
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19 | * from the results of running each element of `object` thru `iteratee`. The
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20 | * corresponding inverted value of each inverted key is an array of keys
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21 | * responsible for generating the inverted value. The iteratee is invoked
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22 | * with one argument: (value).
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23 | *
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24 | * @static
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25 | * @memberOf _
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26 | * @since 4.1.0
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27 | * @category Object
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28 | * @param {Object} object The object to invert.
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29 | * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
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30 | * @returns {Object} Returns the new inverted object.
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31 | * @example
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32 | *
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33 | * var object = { 'a': 1, 'b': 2, 'c': 1 };
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34 | *
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35 | * _.invertBy(object);
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36 | * // => { '1': ['a', 'c'], '2': ['b'] }
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37 | *
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38 | * _.invertBy(object, function(value) {
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39 | * return 'group' + value;
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40 | * });
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41 | * // => { 'group1': ['a', 'c'], 'group2': ['b'] }
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42 | */
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43 | var invertBy = createInverter(function(result, value, key) {
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44 | if (value != null &&
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45 | typeof value.toString != 'function') {
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46 | value = nativeObjectToString.call(value);
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47 | }
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48 |
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49 | if (hasOwnProperty.call(result, value)) {
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50 | result[value].push(key);
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51 | } else {
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52 | result[value] = [key];
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53 | }
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54 | }, baseIteratee);
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55 |
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56 | module.exports = invertBy;
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