if we run 9119 through the function, 811181 will come out, because 92 is 81 and 12 is 1. code example

Example: if we run 9119 through the function, 811181 will come out, because 92 is 81 and 12 is 1.

function squareDigits(num){
    return Number(('' + num).split('').map(function (val) { return val * val;}).join(''));
}