JavaScript - sort in random order

In this short article, we would like to show how to sort array items in random order in JavaScript.

Quick solution:

array.sort(() => Math.random() - 0.5);

Warning: Array sort() method changes input array items order. 

Reusable function

// ONLINE-RUNNER:browser;

const sortRandomly = (array) => array.sort(() => Math.random() - 0.5);


// Usage example:

const array = [1, 2, 3, 4, 5];

console.log(array);   // [1, 2, 3, 4, 5]
sortRandomly(array);  // <----- random sort function call
console.log(array);   // [3, 4, 5, 2, 1]

Fisher–Yates shuffle algorithm

The below example implements Fisher–Yates shuffle algorithm:

// ONLINE-RUNNER:browser;

const randomInteger = (max) => {
    return Math.floor(max * Math.random());
};

const sortRandomly = (array) => {
    for (let i = array.length - 1; i > 0; --i) {
        const j = randomInteger(i + 1);
        const tmp = array[i];
        array[i] = array[j];
        array[j] = tmp;
    }
};


// Usage example:

const array = [1, 2, 3, 4, 5];

console.log(array);   // [1, 2, 3, 4, 5]
sortRandomly(array);  // <----- random sort function call
console.log(array);   // [3, 4, 5, 2, 1]

References

1. Fisher–Yates shuffle - Wikipedia