JSFiddle - React, Tailwind, and code Playground

JavaScript

var coordinates = [];
coordinates[[0, 0, 3, 5]] = "Hello World";

coordinates[[0, 0, 3]] = "Hello World1";

console.log(coordinates[[0, 0, 3]]);
console.log(coordinates[[0, 0, 3, 5]]);
console.log(coordinates.toString());

Object.keys(coordinates).forEach(function(key) {
    console.log(key, coordinates[key]);
});