blob: 54fb1f1bef6bea52c5bab2914a5f24e2e1f88bac [file] [log] [blame]
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;