polyfill of filter in javascript

filterPolyfill.js

Array.prototype.myFilter = function() {
    var arr = this;
    var len = arr.length;
    var fn = arguments[0];
    var newArr = [];
    for (var i=0; i<len; i++) {
        if (fn(arr[i], i, arr)) {
            newArr.push(arr[i]);
        }
    }
    return newArr;

}

var arr = [1, 2, 3, 4, 5, 6, 7, 8];

var filter = arr.filter((item)=>item % 2);
var myFilter = arr.myFilter((item)=>item % 2);

console.log(filter);
// [2,4,6,8]
console.log(myFilter);
// [2,4,6,8]