Array methods

index.js

function forEach(arr, func){
    "use strict";
    for (var i=0, len = arr.length; i<len; i++){
        arr[i] = func(arr[i]);
    }
}

function every(arr, func){
    "use strict";
    var res = null;
    for (var i=0, len = arr.length; i<len; i++){
        res = res && func(arr[i]);
    }
    return res;
}

function some(arr, func){
    "use strict";
    var res = null;
    for (var i=0, len = arr.length; i<len; i++){
        res = res || func(arr[i]);
    }
    return res;
}

function forEach(arr, func){
"use strict";
for (var i=0, len = arr.length; i<len; i++){
arr[i] = func(arr[i]);
}
}

function every(arr, func){
"use strict";
var res = null;
for (var i=0, len = arr.length; i<len; i++){
res = res && func(arr[i]);
}
return res;
}

function some(arr, func){
"use strict";
var res = null;
for (var i=0, len = arr.length; i<len; i++){
res = res || func(arr[i]);
}
return res;
}

function map(arr, func){
"use strict";
var res = [];
for (var i=0, len = arr.length; i<len; i++){
res[i] = func(arr[i]);
}
return res;
}

function filter(arr, func){
"use strict";
var res = [];
for (var i=0, len = arr.length; i<len; i++){
if (func(arr[i]) === true){
res.push(arr[i]);
}
}
return res;
}