How to fill a large matrix with numbers?

Question

JavaScript

There is a matrix 12x31.

I declare it like this

let matrix = [
    [],
    [],
    [],
    [],
    [],
    [],
    [],
    [],
    [],
    [],
    [],
    []
];

Is it possible somehow easier?

And how in this case to fill in order? How to access each row of a matrix? 12 cycles?

Answer 1

[...Array(12)].map(row => [...Array(31)])
fill with numbers - how, from 0 to 12*31?

[...Array(12)].map((row, x) => 
  [...Array(31)].map((col, y) => x * 31 + y)
)

Answer 2

Easier: npm install ml-matrix Documentation

import { Matrix } from 'ml-matrix';

const matrix = new Matrix(12, 31);