You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
60 lines
2.0 KiB
JavaScript
60 lines
2.0 KiB
JavaScript
9 years ago
|
var createAggregator = require('../internal/createAggregator');
|
||
|
|
|
||
|
|
/** 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 keys generated from the results of running
|
||
|
|
* each element of `collection` through `iteratee`. The corresponding value
|
||
|
|
* of each key is an array of the elements responsible for generating the key.
|
||
|
|
* The `iteratee` is bound to `thisArg` and invoked with three arguments:
|
||
|
|
* (value, index|key, collection).
|
||
|
|
*
|
||
|
|
* If a property name is provided for `iteratee` the created `_.property`
|
||
|
|
* style callback returns the property value of the given element.
|
||
|
|
*
|
||
|
|
* If a value is also provided for `thisArg` the created `_.matchesProperty`
|
||
|
|
* style callback returns `true` for elements that have a matching property
|
||
|
|
* value, else `false`.
|
||
|
|
*
|
||
|
|
* If an object is provided for `iteratee` the created `_.matches` style
|
||
|
|
* callback returns `true` for elements that have the properties of the given
|
||
|
|
* object, else `false`.
|
||
|
|
*
|
||
|
|
* @static
|
||
|
|
* @memberOf _
|
||
|
|
* @category Collection
|
||
|
|
* @param {Array|Object|string} collection The collection to iterate over.
|
||
|
|
* @param {Function|Object|string} [iteratee=_.identity] The function invoked
|
||
|
|
* per iteration.
|
||
|
|
* @param {*} [thisArg] The `this` binding of `iteratee`.
|
||
|
|
* @returns {Object} Returns the composed aggregate object.
|
||
|
|
* @example
|
||
|
|
*
|
||
|
|
* _.groupBy([4.2, 6.1, 6.4], function(n) {
|
||
|
|
* return Math.floor(n);
|
||
|
|
* });
|
||
|
|
* // => { '4': [4.2], '6': [6.1, 6.4] }
|
||
|
|
*
|
||
|
|
* _.groupBy([4.2, 6.1, 6.4], function(n) {
|
||
|
|
* return this.floor(n);
|
||
|
|
* }, Math);
|
||
|
|
* // => { '4': [4.2], '6': [6.1, 6.4] }
|
||
|
|
*
|
||
|
|
* // using the `_.property` callback shorthand
|
||
|
|
* _.groupBy(['one', 'two', 'three'], 'length');
|
||
|
|
* // => { '3': ['one', 'two'], '5': ['three'] }
|
||
|
|
*/
|
||
|
|
var groupBy = createAggregator(function(result, value, key) {
|
||
|
|
if (hasOwnProperty.call(result, key)) {
|
||
|
|
result[key].push(value);
|
||
|
|
} else {
|
||
|
|
result[key] = [value];
|
||
|
|
}
|
||
|
|
});
|
||
|
|
|
||
|
|
module.exports = groupBy;
|