blob: 7620aa76195125cb32de065f65bbdf25d688f1b5 [file] [log] [blame]
var arrayFilter = require('../internal/arrayFilter'),
baseCallback = require('../internal/baseCallback'),
baseFilter = require('../internal/baseFilter'),
isArray = require('../lang/isArray');
/**
* Iterates over elements of `collection`, returning an array of all elements
* `predicate` returns truthy 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 _
* @alias select
* @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 new filtered array.
* @example
*
* _.filter([4, 5, 6], function(n) {
* return n % 2 == 0;
* });
* // => [4, 6]
*
* var users = [
* { 'user': 'barney', 'age': 36, 'active': true },
* { 'user': 'fred', 'age': 40, 'active': false }
* ];
*
* // using the `_.matches` callback shorthand
* _.pluck(_.filter(users, { 'age': 36, 'active': true }), 'user');
* // => ['barney']
*
* // using the `_.matchesProperty` callback shorthand
* _.pluck(_.filter(users, 'active', false), 'user');
* // => ['fred']
*
* // using the `_.property` callback shorthand
* _.pluck(_.filter(users, 'active'), 'user');
* // => ['barney']
*/
function filter(collection, predicate, thisArg) {
var func = isArray(collection) ? arrayFilter : baseFilter;
predicate = baseCallback(predicate, thisArg, 3);
return func(collection, predicate);
}
module.exports = filter;