Initialize mapped array
JavaScript, Array · Jun 13, 2023

Initializes and fills an array with the specified values, using a mapping function.
- Use the
Array()
constructor to create an array of the desired length. - Use
Array.prototype.fill()
to fill it withnull
values. - Use
Array.prototype.map()
to fill it with the desired values, using the provided function,mapFn
. - Omit the second argument,
mapFn
, to map each element to its index.
const initializeMappedArray = (n, mapFn = (_, i) => i) => Array(n).fill(null).map(mapFn); initializeMappedArray(5); // [0, 1, 2, 3, 4] initializeMappedArray(5, i => `item ${i + 1}`); // ['item 1', 'item 2', 'item 3', 'item 4', 'item 5']