JSFiddle - React, Tailwind, and code Playground

by Graham Fairweather

JavaScript

var array = [],
    k = 0;

for (var i = 0; i < 10; i++) {
    array[i] = [];
    for (var j = 0; j < 100; j++) {
        k = k + 1
        array[i].push(k);
    }
}

function indexOf2d(arr, val) {
    var index = [-1, -1];

    if (!Array.isArray(arr)) {
        return index;
    }

    arr.some(function (sub, posX) {
        if (!Array.isArray(sub)) {
            return false;
        }

        var posY = sub.indexOf(val);
        
        if (posY !== -1) {
            index[0] = posX;
            index[1] = posY;
            return true;
        }

        return false;
    });

    return index;
}

console.log(indexOf2d(array, 50));