| var isIterateeCall = require('../internal/isIterateeCall'), |
| keys = require('./keys'); |
| |
| /** Used for native method references. */ |
| var objectProto = Object.prototype; |
| |
| /** Used to check objects for own properties. */ |
| var hasOwnProperty = objectProto.hasOwnProperty; |
| |
| /** |
| * Creates an object composed of the inverted keys and values of `object`. |
| * If `object` contains duplicate values, subsequent values overwrite property |
| * assignments of previous values unless `multiValue` is `true`. |
| * |
| * @static |
| * @memberOf _ |
| * @category Object |
| * @param {Object} object The object to invert. |
| * @param {boolean} [multiValue] Allow multiple values per key. |
| * @param- {Object} [guard] Enables use as a callback for functions like `_.map`. |
| * @returns {Object} Returns the new inverted object. |
| * @example |
| * |
| * var object = { 'a': 1, 'b': 2, 'c': 1 }; |
| * |
| * _.invert(object); |
| * // => { '1': 'c', '2': 'b' } |
| * |
| * // with `multiValue` |
| * _.invert(object, true); |
| * // => { '1': ['a', 'c'], '2': ['b'] } |
| */ |
| function invert(object, multiValue, guard) { |
| if (guard && isIterateeCall(object, multiValue, guard)) { |
| multiValue = undefined; |
| } |
| var index = -1, |
| props = keys(object), |
| length = props.length, |
| result = {}; |
| |
| while (++index < length) { |
| var key = props[index], |
| value = object[key]; |
| |
| if (multiValue) { |
| if (hasOwnProperty.call(result, value)) { |
| result[value].push(key); |
| } else { |
| result[value] = [key]; |
| } |
| } |
| else { |
| result[value] = key; |
| } |
| } |
| return result; |
| } |
| |
| module.exports = invert; |