Save with firebase with a dynamic key name

Question

I am trying to insert in my database the month chosen by the user.

saveInBdd (){
  this.errors = [];

  const user = firebase.auth().currentUser;
  user.updateProfile({
    displayName: this.firstname,
  }).then(()=>{
    this.saveUserToUsersRef(user)
  }, error => {
    this.errors.push(error.message)
  })
},
saveUserToUsersRef(user){
  return this.usersRef.child(user.uid).update({
    tab1: { this.months[0].selectedOption : "test"}
  })
},

This code returns this error to me:

Answer 1

The property name of a JSON object in the notation you're using needs to be a literal. To use a variable as the name of a property, use [] notation:

saveUserToUsersRef(user){
  var updates = {};
  updates[this.months[0].selectedOption] = "test";
  return this.usersRef.child(user.uid).update(updates))
},