无法在mounted() 内调用函数

Question

I have a chat API that I'm connecting to a Vue.js project.

When user goes to a chat room page, it sends an ajax request and then calls the function that fetches the whole chat history:

mounted() {
$.ajax({
  url: `http://localhost:8000/api/rooms/${this.$route.params.id}/`,
  data: {username: this.username},
  type: 'PATCH',
  success: (data) => {
    const user = data.members.find((member) => JSON.parse(member).username === this.username)

    if (user) {
      // The user belongs/has joined the session
      this.fetchChatSessionHistory(this.$route.params.id)
    }
  }
})


},

  fetchChatSessionHistory (uri) {
    $.get(`http://127.0.0.1:8000/api/rooms/${uri}/messages/`, (data) => {
      this.messages = data.messages
    })
  },

but it fails with:

TypeError: _this.fetchChatSessionHistory is not a function

I understand that it might be defined at a wrong place but I have no idea how do it right.

Answer 1

You should put that function inside methods property as follows :

mounted(){
      ...
      },
 methods:{
     fetchChatSessionHistory (uri){
         ....
      }
   }

Answer 2

You can do the following:

mounted() {
    var _this = this;
    $.ajax({
        url: `http://localhost:8000/api/rooms/${this.$route.params.id}/`,
        data: {username: _this.username},
        type: 'PATCH',
        success: (data) => {
        const user = data.members.find((member) => JSON.parse(member).username === _this.username)

        if (user) {
            // The user belongs/has joined the session
            _this.fetchChatSessionHistory(_this.$route.params.id)
        }
    })
}