Function to create array of N empty arrays in javascript

Question

I'm looking for an implementation of createEmpties(nValues) as below:

var result = createEmpties(4);
console.log(result)

[[], [], [], []]

I tried using map:

new Array(nValues).map(_ => []);

but got this output:

[ <4 empty items> ]

Answer 1

The new Array, will not fill. Try Array(nValues).fill(null).map(_ => []). This should give you what you are looking for.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill

Answer 2

You can do it using Array.from.

const result = Array.from({ length: 4 }, () => []);
console.log(result);

Answer 3

Here's a function that gives you exactly what you asked for:

function createEmpties(n) {
    return Array(n).fill(new Array());
}

var result = createEmpties(4);
console.log(result)