JS判断一个数组中是否有重复值的三种方法

   function isRepeat(list,type){
        let nary = list.sort();
        let isPass = true;
        for(var i=0;i<list.length;i++){
          if (nary[i]==nary[i+1]){
            isPass = false;
            break;
          }
        }
        return isPass;
     }

function isRepeat(arr){
  var hash = {};
  for(var i in arr) {
    if(hash[arr[i]])   return true;
    hash[arr[i]] = true;
  }
  return false;
}

function isRepeat(arr){
  var s = ary.join(",")+",";
  for(var i=0;i<ary.length;i++) {
    if(s.replace(ary[i]+",","").indexOf(ary[i]+",")>-1) {
        alert("数组中有重复元素：" + ary[i]);
        break;
    }
  }
}