好像不是最全的数组去重方法

这一篇文章，我们讲解一下数组去重。1.最简单粗暴地方式，两重for循环let arr = [9, 5, 6, 5, ‘1’, ‘1’, true, 5, true];for (var i = 0; i < arr.length; i++) { for (var j = i + 1; j < arr.length; j++) { if(arr[i] === arr[j]){ arr.splice(j,1); } }}console.log(arr); // [9, 5, 6, “1”, true, undefined, null, NaN, NaN, {…}, {…}]// 两个NaN, 因为NaN!=NaN2.indexOflet a = [];for (var i = 0; i < arr.length; i++) { if(a.indexOf(arr[i]) === -1){ a.push(arr[i]); }}console.log(a); // [9, 5, 6, “1”, true, undefined, null, NaN, NaN, {…}, {…}]// 两个NaN, 因为NaN!=NaN3.includesfor (var i = 0; i < arr.length; i++) { if(!a.includes(arr[i])){ a.push(arr[i]); }}console.log(a); // [9, 5, 6, “1”, true, undefined, null, NaN, {…}, {…}]4.Setlet a = […(new Set(arr))];console.log(a); // [9, 5, 6, “1”, true, undefined, null, NaN, {…}, {…}]5.filterlet a = arr.filter(function(value, index){ return arr.indexOf(value, 0) === index;})console.log(a);// [9, 5, 6, “1”, true, undefined, null, {…}, {…}]arr.filter(function(value){ return a.indexOf(value) === -1 ? a.push(value) : a;})console.log(a);// [9, 5, 6, “1”, true, undefined, null, NaN, NaN, {…}, {…}]6.sortarr = arr.sort(); // 排序，如果相同就会挨着a.push(arr[0]); // 先放数组第一个元素for (var i = 1; i < arr.length; i++) { if(arr[i] !== arr[i - 1]){ a.push(arr[i]); }}7.reducearr = arr.sort(); arr.reduce(function(preVal, nowVal){ if(preVal !== nowVal){ a.push(preVal); } return nowVal;}, a)arr.reduce(function(preVal, nowVal){ return a.indexOf(nowVal) === -1 ? a.push(nowVal) : a;}, a)console.log(a); //[“1”, 5, 6, 9, NaN, NaN, {…}, {…}, null, true, undefined]8.hasOwnPropertylet obj = {};for (var i = 0; i < arr.length; i++) { if(!obj.hasOwnProperty(obj[typeof arr[i] + arr[i]])){ obj[typeof arr[i] + arr[i]] = arr[i]; }}console.log(Object.values(obj)); //[9, 5, 6, “1”, true, undefined, null, NaN, {…}] 无法判断对象9.对象数组去重方法let obj = {};for (var i = 0; i < arr.length; i++) { if(!obj[typeof arr[i] + arr[i]]){ obj[typeof arr[i] + arr[i]] = arr[i]; }}console.log(Object.values(obj)); //[9, 5, 6, “1”, true, undefined, null, NaN, {…}]10.Maplet map = new Map();for (var i = 0; i < arr.length; i++) { if(!map.get(arr[i])){ map.set(arr[i], arr[i]); }}console.log(map);补充我想说一下forEach与maparr.forEach( function(element, index) { console.log(element);});arr.map(function(element, index){ console.log(element);});相同点他们都是用来遍历数组的。不同点map能有返回值，forEach没有返回值。let arr = [9,3,6,3,6,3];arr = arr.forEach( function(element, index) { return element + 1;});console.log(arr); // undefinedarr = arr.map(function(element, index){ return element + 1;});console.log(arr); //[10, 4, 7, 4, 7, 4]forEach不能中途打断let arr = [9,3,6,3,6,3];arr.forEach( function(element, index) { console.log(element); if(index === 2){ return; //没用，break,continue会报错是无效的 }});forEach模拟实现Array.prototype.bforEach = function (fn) { let array = this; for (var i = 0; i < array.length; i++) { fn(array[i], i, array); }}arr.bforEach(function(element, index){ console.log(element); // 9, 3, 6, 3, 6, 3});map模拟实现Array.prototype.Map = function (fn) { let array = this, a = [], r; for (var i = 0; i < array.length; i++) { r = fn(array[i], i, array); a.push(r); } return a;}喜欢的可以点一个赞，或者关注一下。鼓励一下一名自学前端的大学生。