JS two methods to determine whether there are duplicate values in the array

Determine if there are duplicate values in the array , If it is repeated, it will prompt that the priority is repeated

The first method recommend

//  Array value as key , Continue adding values to an object ,
    //  If you find that this attribute already exists in the object before adding value , Then he is repeating 
function  isRepeat(arr) {
    
      var hash = {
    }
      for (var i in arr) {
    
        if (hash[arr[i]]) {
     return true }
        hash[arr[i]] = true
      }
      return false
    },

All the code

<Input v-model.trim="item.haha" @on-blur="func1" clearable placeholder=" Please enter " :style="{ width: formInputWidth1 }"></Input>
//  Array value as key , Continue adding values to an object ,
//  If you find that this attribute already exists in the object before adding value , Then he is repeating 
isRepeat(arr) {
    
  var hash = {
    }
  for (var i in arr) {
    
    if (hash[arr[i]]) {
     return true }
    hash[arr[i]] = true
  }
  return false
},
func1() {
    
  let list = []
  this.form2.items.forEach(item => {
     // this.form2.items  It's my data 
    list.push(item.haha) // item.haha  Is the data I want to check for duplicates 
  })
  let temp = this.isRepeat(list) //  If there is a repetition, it returns true, Otherwise false
  // let temp = this.arrHasvalue(list)  The second method is not recommended , There is a problem 
  if (temp) {
    
    this.$Message.error({
     content: ' Priority has duplicate , Please check !', duration: 3 })
  }
  console.log(list, temp, ' priority ', this.$cloneDeep(this.form2.items))
},

The second method Not recommended

function arrHasvalue(arr) {
    
      var nary = arr.sort()
      for (var i = 0; i < arr.length; i++) {
    
        if (nary[i] == nary[i + 1]) {
    
          console.log(' Array duplicates ：' + nary[i])
          return true
        } else {
    
          return false
        }
      }
    },