Vue is warning that duplicate keys have been detected, specifically with key x. This could potentially lead to an update error. It is important to prevent adding an item that has already been

I'm working with a v-autocomplete that iterates through a list of users. Once I select a user and add them to another list using a button click, I want to prevent adding the same user again by comparing their unique key. How can I implement an alert if a user has already been added?

<v-autocomplete
    v-model="event.user"
    :items="usersData"
    label="Search for speakers"
    :search-input.sync="searchUser"
    return-object
    item-value="id"
    item-text="name"
></v-autocomplete>

Here is my method to add a speaker:

addSpeaker() {
    const newSpeaker = {
        id: this.event.user.uid,
        name: this.event.user.name,
    }
    this.speakers.push(newSpeaker)
    this.event.user = ''
},
removeSpeaker(id) {
    this.speakers = this.speakers.filter(speaker => speaker.id !== id)
}

Is there a way to check here and avoid adding a user multiple times?

Answer №1

Verify the existence of a user by their id. If the user is found, display an error message; otherwise, add the user:

addSpeaker () {
  const newSpeaker = {
    id: this.event.user.uid,
    name: this.event.user.name,
  }

  let doesUserExist = false;

  for (let i = 0; i < this.speakers.length; i++) {
    if (this.speakers[i].id === newSpeaker.id) {
      // Display an error indicating that the user already exists

      doesUserExist = true;

      break;
    }
  }

  if (!doesUserExist) {
    this.speakers.push(newSpeaker);
  }

  this.event.user = ''
},

Alternatively, you can use a forEach loop:

...

this.speakers.forEach(function(speaker) {
  if (this.speakers[i].id === newSpeaker.id) {
    // Display an error indicating that the user already exists

    doesUserExist = true;

    return;
  }
});

...

Answer №2

you could utilize findIndex method to improve efficiency

addNewSpeaker() {
  const speaker = {
    id: this.currentEvent.user.identifier,
    name: this.currentEvent.user.fullName
  };
  const isUnique = this.allSpeakers.findIndex(item => item.name === this.currentEvent.user.fullName) === -1;
  isUnique && this.allSpeakers.push(speaker);
  this.currentEvent.user = "";
}

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