JavaScript去掉数组中的重复元素

(function() {
 'use strict';
 function filter1(arr) {
 var b = [];
 arr.forEach(function(i) {
 if (b.indexOf(i) == -1) {
 b.push(i);
 }
 });
 return b;
 }
 
 function filter2(arr) {
 var b = {}, c = [];
 arr.forEach(function(i) {
 b[i] = b[i] ? b[i] : {};
 var type = typeof i;
 if (!b[i][type]) {
 b[i][type] = true;
 c.push(i);
 }
 });
 return c;
 }
 
 function timer(fn, arr) {
 console.time('filter');
 fn.call(this, arr);
 console.timeEnd('filter');
 }
 
 function testArr(n) {
 // var arr = [4,3,"3",3,5,7,5];
 var arr = [];
 for (var i = 0; i < n; i++) {
 arr.push(i);
 arr.push(i + "");
 }
 return arr;
 }
 
 for (var i = 1; i <= 100; i++) {
 console.log(i * 10);
 var arr = testArr(i * 10);
 timer(filter1, arr);
 timer(filter2, arr);
 }
})();