dotfiles/.vscode/extensions/vscodevim.vim-0.1.10/node_modules/lodash/sampleSize.js

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2016-09-11 09:29:13 +01:00
var baseClamp = require('./_baseClamp'),
baseRandom = require('./_baseRandom'),
isIterateeCall = require('./_isIterateeCall'),
toArray = require('./toArray'),
toInteger = require('./toInteger');
/**
* Gets `n` random elements at unique keys from `collection` up to the
* size of `collection`.
*
* @static
* @memberOf _
* @since 4.0.0
* @category Collection
* @param {Array|Object} collection The collection to sample.
* @param {number} [n=1] The number of elements to sample.
* @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
* @returns {Array} Returns the random elements.
* @example
*
* _.sampleSize([1, 2, 3], 2);
* // => [3, 1]
*
* _.sampleSize([1, 2, 3], 4);
* // => [2, 3, 1]
*/
function sampleSize(collection, n, guard) {
var index = -1,
result = toArray(collection),
length = result.length,
lastIndex = length - 1;
if ((guard ? isIterateeCall(collection, n, guard) : n === undefined)) {
n = 1;
} else {
n = baseClamp(toInteger(n), 0, length);
}
while (++index < n) {
var rand = baseRandom(index, lastIndex),
value = result[rand];
result[rand] = result[index];
result[index] = value;
}
result.length = n;
return result;
}
module.exports = sampleSize;