indexOf去重

  1. const array = [2,22,13,4,2,2]
  2. let newArray = []
  3. for(let key of array){
  4.     if(newArray.indexOf(key) === -1){
  5.       newArray.push(key)
  6.   }
  7. }

哈希去重

  1. var newArr = [];
  2. var obj = {}
  3. for (var i = 0; i < arr.length; i++) {
  4.     if (obj[typeof arr[i] + arr[i]] == undefined) {
  5.         newArr.push(arr[i]);
  6.         obj[typeof arr[i] + arr[i]] = true;
  7.     }
  8. }

ES6 set数据结构

  1. let set=new Set(arr);
  2. let newArr=[...set];
  3. // 或者
  4. let newArr=Array.from(set);

ES6 map数据结构

  1.  const map = new Map();
  2.  arr.filter((item)=>!map.has(item)&&map.set(item,1))

includes

判断数组是否包含某个值，返回Boolean值

  1. var newArr=[];
  2. for(var i in arr){
  3.     if(!newArr.includes(arr[i])){
  4.         newArr.push(arr[i])
  5.     }
  6. }

之后再陆续学习补充……