Clear from options Select in vue.js on new line?

Question

Vue.js

<div id="app">
  <h1>Add user</h1>
  <div v-for="(user, index) in users">
    <select v-model="user.title"  @change="changeUser">
      <option value="">Выбрать</option>
      <option v-for="o in getOptions(index)" :value="o.id" v-text="o.title"></option>
    </select>
    <select v-model="user.weight" >
    <option value="">Выбрать</option>
      <option v-for="o in getOptions2(index)" :value="o.id" v-text="o.title"></option>
    </select>

    <button @click="deleteUser(index)">
      delete
    </button>
  </div>

  <button @click="addUser" :disabled="users.length >= options.length">
    New User
  </button>

  <pre>{{ users.title }}</pre>
  <pre>{{ percentTotal }}</pre>

</div>

new Vue({
  el: '#app',
  data: {
    users: [{ name: '', percent: '' }],
    options: [
      { title: '', id: '' },

    ],
    options2: [
      { title2: '', id2: '' },
    
    ]
  },
  methods: {
    getOptions(index) {
      return this.options.filter(o => this.users.every((u, i) => u.title !== o.id || i === index));
    },
    getOptions2(index) {
      return this.options2;
    },
    addUser(index) {
      this.users.push({ title: '',percent:'' });
      this.users.weight='';
      
    },
    changeUser()
    {
    	var vm = this
    		 fetch('https://jsonplaceholder.typicode.com/photos')
      .then(function (response) {
        return response.json()
      })
      .then(function (data) {
        vm.options2 = data
      })
    },
    deleteUser(index) {
      this.users.splice(index, 1);
      if (this.users.length === 0) {
        this.addUser();
      }
    },
    
  },

   created: function () {
    // Alias the component instance as `vm`, so that we  
    // can access it inside the promise function
    var vm = this
    // Fetch our array of posts from an API
    fetch('https://jsonplaceholder.typicode.com/posts')
      .then(function (response) {
        return response.json()
      })
      .then(function (data) {
        vm.options = data
      })
  },
   computed: {
    percentTotal() {
      return this.users.reduce((acc, user) => acc + parseInt(user.percent, 10), 0)
    },
     
  },
 
});

Question: how to clear 2 selects when adding a new line, only for a new line?

Answer 1

You don't need to clean anything. Let each element have its own options. In the template of the second select, change
v-for="o in getOptions2(index)"to v-for="o in user.options"; in the change handler of the first select, pass the current object: @change="changeUser(user)", and accordingly, put the received data in this object instead of options2 (just cut them out):

changeUser(user) {
  fetch('https://jsonplaceholder.typicode.com/photos')
    .then(r => r.json())
    .then(d => this.$set(user, 'options', d));
},