Files
lodash/lodash.invert/index.js
John-David Dalton afaae9f972 Bump to v4.1.1.
2018-02-03 19:13:40 -08:00

122 lines
3.2 KiB
JavaScript

/**
* lodash (Custom Build) <https://lodash.com/>
* Build: `lodash modularize exports="npm" -o ./`
* Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
* Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
* Available under MIT license <https://lodash.com/license>
*/
var baseFor = require('lodash._basefor'),
keys = require('lodash.keys');
/**
* The base implementation of `_.forOwn` without support for iteratee shorthands.
*
* @private
* @param {Object} object The object to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @returns {Object} Returns `object`.
*/
function baseForOwn(object, iteratee) {
return object && baseFor(object, iteratee, keys);
}
/**
* The base implementation of `_.invert` and `_.invertBy` which inverts
* `object` with values transformed by `iteratee` and set by `setter`.
*
* @private
* @param {Object} object The object to iterate over.
* @param {Function} setter The function to set `accumulator` values.
* @param {Function} iteratee The iteratee to transform values.
* @param {Object} accumulator The initial inverted object.
* @returns {Function} Returns `accumulator`.
*/
function baseInverter(object, setter, iteratee, accumulator) {
baseForOwn(object, function(value, key, object) {
setter(accumulator, iteratee(value), key, object);
});
return accumulator;
}
/**
* Creates a function like `_.invertBy`.
*
* @private
* @param {Function} setter The function to set accumulator values.
* @param {Function} toIteratee The function to resolve iteratees.
* @returns {Function} Returns the new inverter function.
*/
function createInverter(setter, toIteratee) {
return function(object, iteratee) {
return baseInverter(object, setter, toIteratee(iteratee), {});
};
}
/**
* 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.
*
* @static
* @memberOf _
* @since 0.7.0
* @category Object
* @param {Object} object The object to invert.
* @returns {Object} Returns the new inverted object.
* @example
*
* var object = { 'a': 1, 'b': 2, 'c': 1 };
*
* _.invert(object);
* // => { '1': 'c', '2': 'b' }
*/
var invert = createInverter(function(result, value, key) {
result[value] = key;
}, constant(identity));
/**
* Creates a function that returns `value`.
*
* @static
* @memberOf _
* @since 2.4.0
* @category Util
* @param {*} value The value to return from the new function.
* @returns {Function} Returns the new constant function.
* @example
*
* var object = { 'user': 'fred' };
* var getter = _.constant(object);
*
* getter() === object;
* // => true
*/
function constant(value) {
return function() {
return value;
};
}
/**
* This method returns the first argument given to it.
*
* @static
* @since 0.1.0
* @memberOf _
* @category Util
* @param {*} value Any value.
* @returns {*} Returns `value`.
* @example
*
* var object = { 'user': 'fred' };
*
* _.identity(object) === object;
* // => true
*/
function identity(value) {
return value;
}
module.exports = invert;