Repeat an array with multiple elements multiple times in JavaScript
No need for any library, you can use Array.from to create an array of arrays you want repeated, and then flatten using [].concat and spread:
const makeRepeated = (arr, repeats) => [].concat(...Array.from({ length: repeats }, () => arr)); console.log(makeRepeated([1, 2, 3], 2));On newer browsers, you can use Array.prototype.flat instead of [].concat(...:
const makeRepeated = (arr, repeats) => Array.from({ length: repeats }, () => arr).flat(); console.log(makeRepeated([1, 2, 3], 2));
You can use the Array constructor along with its fill method to fill it a number of times of the array you want to repeat, then concat them (the subarrays) into a single array:
const repeatedArray = [].concat(...Array(num).fill(arr));Note: On older browsers (pre-ES6), you can use Function#apply to mimic the rest syntax above (concat will be called with each of the sub arrays passed to it as argument):
var repeatedArray = [].concat.apply([], Array(num).fill(arr));Example:
const repeat = (a, n) => Array(n).fill(a).flat(1)console.log( repeat([1, 2], 3) )Recursive alternative:
const repeat = (a, n) => n ? a.concat(repeat(a, --n)) : [];console.log( repeat([1, 2], 3) )