blob: 481c7e4e3559452ceb6207120346c76b3eb2363c [file] [log] [blame]
/**
* Lo-Dash 2.4.1 (Custom Build) <http://lodash.com/>
* Build: `lodash modularize exports="node" -o ./compat/`
* Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
* Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
* Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
* Available under MIT license <http://lodash.com/license>
*/
var baseRandom = require('../internals/baseRandom'),
isString = require('../objects/isString'),
shuffle = require('./shuffle'),
support = require('../support'),
values = require('../objects/values');
/* Native method shortcuts for methods with the same name as other `lodash` methods */
var nativeMax = Math.max,
nativeMin = Math.min;
/**
* Retrieves a random element or `n` random elements from a collection.
*
* @static
* @memberOf _
* @category Collections
* @param {Array|Object|string} collection The collection to sample.
* @param {number} [n] The number of elements to sample.
* @param- {Object} [guard] Allows working with functions like `_.map`
* without using their `index` arguments as `n`.
* @returns {Array} Returns the random sample(s) of `collection`.
* @example
*
* _.sample([1, 2, 3, 4]);
* // => 2
*
* _.sample([1, 2, 3, 4], 2);
* // => [3, 1]
*/
function sample(collection, n, guard) {
if (collection && typeof collection.length != 'number') {
collection = values(collection);
} else if (support.unindexedChars && isString(collection)) {
collection = collection.split('');
}
if (n == null || guard) {
return collection ? collection[baseRandom(0, collection.length - 1)] : undefined;
}
var result = shuffle(collection);
result.length = nativeMin(nativeMax(0, n), result.length);
return result;
}
module.exports = sample;