diff --git a/snippets/shuffle.md b/snippets/shuffle.md index 27d7fd783..54687f67f 100644 --- a/snippets/shuffle.md +++ b/snippets/shuffle.md @@ -1,10 +1,17 @@ ### shuffle -Randomizes the order of the values of an array. +Randomizes the order of the values of an array, in place. -Use `Array.sort()` to reorder elements, using `Math.random()` in the comparator. +Uses the Fisher-Yates algoritm to reorder the elements of the array, based on the [Lodash implimentation](https://github.com/lodash/lodash/blob/b2ea6b1cd251796dcb5f9700c4911a7b6223920b/shuffle.js) ```js -const shuffle = arr => arr.sort(() => Math.random() - 0.5); +const shuffle = ([...arr]) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr; +}; // shuffle([1,2,3]) -> [2,3,1] ```