how to define 2d array with size empty array in javascript code example

Example 1: javscript generate empty 2d array

var grid = [...Array(width)].map(e => Array(height));
// access via grid[y][x]

Example 2: javascriopt initialize 2d array with size

function makeArray(w, h, val) {
    var arr = [];
    for(let i = 0; i < h; i++) {
        arr[i] = [];
        for(let j = 0; j < w; j++) {
            arr[i][j] = val;
        }
    }
    return arr;
}