Why vue.js component is not set the Data from method

Question

I successfully get data from an Axios request. then assign to data users but it show error. Type Error: Cannot set properties of undefined (setting 'users').

here is my code.

     <template>
        <div class="p-5">
    
            <h1 class="text-2xl mb-4">Certifly Live Video Chat </h1>
            <div id ="users">
            </div>
            <div id="myid" class="grid grid-flow-row grid-cols-3 grid-rows-3 gap-4 bg-black/]">
                <button class="btn btn-info" style="margin-right:5px" v-for="user in users" @click="getAccessToken(user.appt_room_name)" > 
                    {{user.appt_admin_name}} {{user.appt_date_time}}
                </button>
    
                <br><br>
                <div id="video-chat-window">
                </div> 
            </div>
    
        </div>
    </template>
<script>
         export default {
                name: 'video-chat',        
                data() {
                    return {
                        users:[]
                    };
                },         
                methods : {
                     userRequests: function(){
                        axios.post(`/api/user_requests`)
                        .then(function (response) {
                            console.log(response.data)
                            this.users = response.data.data;  
                        })
                        .catch(function (error) {
                            console.log(error);
                        }) 
                    }, 
        
        
                     
                },
                mounted : function () { 
                    this.userRequests();
                }
            }
</script>

console data [ { "id": 1, "appt_date_time": "03:00 - 03:15", "appt_admin_id": 15, "appt_admin_name": "Osana Shiraz", "appt_usr_id": 280965, "appt_usr_name": "Hamza Shiraz", "appt_room_name": "RMX:280965", "created_at": "2021-12-21 14:50:59", "updated_at": "2021-12-21 14:50:59" }, { "id": 3, "appt_date_time": "04:30 - 04:45", "appt_admin_id": 15, "appt_admin_name": "Osana Shiraz", "appt_usr_id": 280965, "appt_usr_name": "awais", "appt_room_name": "RMX:280965", "created_at": "2021-12-21 17:04:09", "updated_at": "2021-12-21 17:04:09" }, { "id": 4, "appt_date_time": "05:15 - 05:30", "appt_admin_id": 15, "appt_admin_name": "Osana Shiraz", "appt_usr_id": 280965, "appt_usr_name": "awais", "appt_room_name": "RMX:280965", "created_at": "2021-12-21 17:06:50", "updated_at": "2021-12-21 17:06:50" } ];

Answer 1

You don't have access to this in your .then callback. So you're trying to assign something to users on undefined. This article explains the reason why. Try changing your promise callback to use an arrow function, such as:

userRequests: function() {
  axios.post('/api/user_requests')
  .then(response => {
    console.log(response.data)
        this.users = response.data.data;
    })
    .catch(function (error) {
        console.log(error);
    }) 
}

Answer 2

If you don't want to use arrow function, you can also save this reference and use it later in the function. Make sure to do this before the axios call.

userRequests: function() {
  let vm = this
  axios.post(`/api/user_requests`).then(function (response) {
    vm.users = response.data.data
  }).catch(function (error) {
    console.log(error)
  }) 
}, 

Answer 3

Try this way

export default {
  name: "videoChat",
  data() {
    return {
      users: [],
    };
  },
  methods: {
    async userRequests() {
      try {
        const { data } = await axios.post(`/api/user_requests`);
        this.users = data;
      } catch (error) {
          console.log('error', error)
      }
    },
  },
  mounted() {
    this.userRequests();
  },
};

Answer 4

Assign to users[] just response.data and not response.data.data . Here you have a functional example: https://codepen.io/jssDev-/pen/zYEExbq