nsq/nsqadmin/node_modules/underscore/amd/sample.js

define(['./_isArrayLike', './clone', './values', './_getLength', './random'], function (_isArrayLike, clone, values, _getLength, random) {

  // Sample **n** random values from a collection using the modern version of the
  // [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher–Yates_shuffle).
  // If **n** is not specified, returns a single random element.
  // The internal `guard` argument allows it to work with `_.map`.
  function sample(obj, n, guard) {
    if (n == null || guard) {
      if (!_isArrayLike(obj)) obj = values(obj);
      return obj[random(obj.length - 1)];
    }
    var sample = _isArrayLike(obj) ? clone(obj) : values(obj);
    var length = _getLength(sample);
    n = Math.max(Math.min(n, length), 0);
    var last = length - 1;
    for (var index = 0; index < n; index++) {
      var rand = random(index, last);
      var temp = sample[index];
      sample[index] = sample[rand];
      sample[rand] = temp;
    }
    return sample.slice(0, n);
  }

  return sample;

});