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JavaScript

var createAggregator = require('../internal/createAggregator');
/**
* Creates an array of elements split into two groups, the first of which
* contains elements `predicate` returns truthy for, while the second of which
* contains elements `predicate` returns falsey for. The predicate is bound
* to `thisArg` and invoked with three arguments: (value, index|key, collection).
*
* If a property name is provided for `predicate` 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 `predicate` 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} [predicate=_.identity] The function invoked
* per iteration.
* @param {*} [thisArg] The `this` binding of `predicate`.
* @returns {Array} Returns the array of grouped elements.
* @example
*
* _.partition([1, 2, 3], function(n) {
* return n % 2;
* });
* // => [[1, 3], [2]]
*
* _.partition([1.2, 2.3, 3.4], function(n) {
* return this.floor(n) % 2;
* }, Math);
* // => [[1.2, 3.4], [2.3]]
*
* var users = [
* { 'user': 'barney', 'age': 36, 'active': false },
* { 'user': 'fred', 'age': 40, 'active': true },
* { 'user': 'pebbles', 'age': 1, 'active': false }
* ];
*
* var mapper = function(array) {
* return _.pluck(array, 'user');
* };
*
* // using the `_.matches` callback shorthand
* _.map(_.partition(users, { 'age': 1, 'active': false }), mapper);
* // => [['pebbles'], ['barney', 'fred']]
*
* // using the `_.matchesProperty` callback shorthand
* _.map(_.partition(users, 'active', false), mapper);
* // => [['barney', 'pebbles'], ['fred']]
*
* // using the `_.property` callback shorthand
* _.map(_.partition(users, 'active'), mapper);
* // => [['fred'], ['barney', 'pebbles']]
*/
var partition = createAggregator(function(result, value, key) {
result[key ? 0 : 1].push(value);
}, function() { return [[], []]; });
module.exports = partition;