get_products_of_all_ints_except_at_index.js

var arr =   [1, 7, 3, 4];

var brute = function(arr) {
 	var i = 0;
    var final_arr = [];
    var temp_arr;
    var j;
    for (i; i < arr.length; i++) {
        temp_arr = arr.slice();
        temp_arr.splice(i, 1);
        final_arr.push(temp_arr[0]);
        for (j = 1; j < temp_arr.length; j++) {
            final_arr[final_arr.length - 1] *= temp_arr[j];
        }
    }
    return final_arr;
}

var nPlus = function(arr) {
    var i = 0;
    var final_arr = [];
    var j;
    var total_trailing_mult = 1;
    for (i; i < arr.length; i++) {
        final_arr.push(total_trailing_mult);
        for (j = i+1; j < arr.length; j++) {
            final_arr[final_arr.length - 1] *= arr[j];
        }
    	total_trailing_mult *= arr[i];
    }
    return final_arr;
}

var n = function(arr) {
    var i = 0;
    var final_arr = Array.apply(null, Array(arr.length)).map(function() { return 1 })
    var total_trailing_mult = 1;
    var total_leading_mult = 1;
    for (i; i < arr.length; i++) {
        final_arr[i] *= total_trailing_mult;
        final_arr[(arr.length - 1) - i] *= total_leading_mult;
        total_trailing_mult *= arr[i];
        total_leading_mult *= arr[(arr.length - 1) - i];
    }
    return final_arr;
}

console.log(n(arr));