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60 lines
1.5 KiB
60 lines
1.5 KiB
var isIterateeCall = require('../internal/isIterateeCall'),
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keys = require('./keys');
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/** Used for native method references. */
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var objectProto = 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 `multiValue` 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} [multiValue] Allow multiple values per key.
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* @param- {Object} [guard] Enables use as a callback 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 `multiValue`
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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, multiValue, guard) {
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if (guard && isIterateeCall(object, multiValue, guard)) {
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multiValue = undefined;
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}
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var index = -1,
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props = keys(object),
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length = props.length,
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result = {};
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while (++index < length) {
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var key = props[index],
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value = object[key];
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if (multiValue) {
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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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}
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return result;
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}
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module.exports = invert;
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