higher-order-functions.js

var each = function(list, f) {
    for (var i = 0; i < list.length; i++) {
        f(list[i]);
    }
};

var map = function(list, f) {
    var arr = [];
    for (var i = 0; i < list.length; i++) {
        arr.push(f(list[i]));
    }
    return arr;
};

var numbers = [0,1,2,3,4,5];


each(numbers, function(x) { console.log(x+1); });
map(numbers, function(x) { return x + 1; });