Return value of recursive function is 'undefined'

Question

Whenever I execute this snippet the console.log before return returns the array with 20 times the value 23. However console.log(Check(users, 0, 20)); returns only \'undefine

Answer 1

You forgot to return a result from the point, where you entering recusrion.

var users = [23, 23, 23, 23, 23, 23, 23, 23, 23, 23];
console.log(Check(users, 0, 20));

function Check(ids, counter, limit){
    ids.push(23);

    // Recursion
    if (counter+1 < limit){
        return Check(ids, counter+1, limit); // return here!
    }
    else {
        console.log(ids);
        return ids;
    }
} 

But return value seems useless, cause' your function altering initial array as well.