数组去重

冒泡法

var array1 = [1, 1, 1, 2, 3, 2, 4];
for(var i=0;i<array1.length;i++) {
  for(j=i+1;j<array1.length;j++){
    if(array1[i]==array1[j]){
      array1.splice(i,1);
      i--;//删除一个以后，这个i之后的所有下标都减去了1.
   }
  }

forEach

var array1 = [1, 1, 1, 2, 3, 2, 4];
var tmpObj = {};
var result = [];
array1.forEach(function(a) {
  var key = (typeof a) + a;
  if (!tmpObj[key]) {
    tmpObj[key] = true;
    result.push(a);
  }
});

es6的set 和Array.from

let array = [1, 1, 1, 1, 2, 3, 4, 4, 5, 3];
let set = new Set(array)
let newArray=Array.from(set)

es6的set 和展开符...

let array = [1, 1, 1, 1, 2, 3, 4, 4, 5, 3];
var a=[...new Set(array)];