Want to implement a function to add buttons. Vue

there are now two arrays. An array A, an array B.
wants to achieve such a function: click the button in array A to add it to array B (implemented here).
if there is this button in array B, it prompts "Don"t repeat it."
I wrote it in VUE. Now the pop-up prompt is stuck here.
Code:

Array An and buttons:

    data() {
      return {
        lablelist: [
          {
            name: ""
          },
          {
            name: ""
          },
          {
            name: ""
          },
          {
            name: ""
          },
          {
            name: ""
          },
           ],
        }

        <el-button v-for="(item,key) in lablelist" 
        type="primary" icon="el-icon-circle-plus-outline" round plain size="small"
          native-type="button" @click="lablebtnitem(item,key)">{{item.name}}
        </el-button>

Array B and buttons:

    waitLoadList: []

        <el-button v-for="(item,index) in waitLoadList" type="success" 
        icon="el-icon-circle-plus-outline" round plain
          size="small" native-type="button" 
          @click="waitlloadbtn(item,index)">{{item.name}}</el-button>

JS:

      lablebtnitem(item) {
        console.log(item)
        let array = this.waitLoadList
        if (array.length == 0) {
          this.waitLoadList.push({
            name: item.name
          })
          //   this.waitLoadList = this.waitLoadList
        } else {
          array.forEach((data, idx) => {
            console.log(data.name)
            if (data.name.indexOf(item.name) == -1) {
              this.waitLoadList.push({
                name: item.name
              })
              return true
            } else {
              //  
              alert("")
              return false
              //   this.waitLoadList = this.waitLoadList
            }
          })
        }
      },

now click the first button to add one, the second button to add one, and the third button to add something wrong at the beginning. It"s starting to change a lot.

lablebtnitem(item) { console.log(item) let array = this.waitLoadList if (array.length == 0) { this.waitLoadList.push({ name: item.name }) // this.waitLoadList = this.waitLoadList } else { let hasVal = array.some((data, idx) => { return data.name === item.name; }); if (!hasVal) { this.waitLoadList.push({ name: item.name }) return true } else { // alert("") return false // this.waitLoadList = this.waitLoadList } } },

this: lablebtnitem(item) { const _this = this console.log(item) let array = _this.waitLoadList if (array.length == 0) { _this.waitLoadList.push({ name: item.name }) // _this.waitLoadList = _this.waitLoadList } else { array.forEach((data, idx) => { console.log(data.name) if (data.name.indexOf(item.name) == -1) { _this.waitLoadList.push({ name: item.name }) return true } else { // alert("") return false // _this.waitLoadList = _this.waitLoadList } }) } },