Access component's this inside firebase promise reposonse - vue.js

Question

I've tried to bind it like it doesn't seem to make the trick :)
firebaseInstance.auth().fetchSignInMethodsForEmail(this.signUpData.email)
.then((response) => {
... all logic
}).bind(this)
...since it outputs the following error:
firebaseInstance.auth(...).fetchSignInMethodsForEmail(...).bind is not a function
Here is the component's logic, can someone please suggest a proper way to access this after firebase response resolves? :bowing:
import { VALIDATION_MESSAGES, VALUES } from './signup.module.config'
import GLOBAL_EVENTS from 'values/events'
import { firebaseInstance } from 'database'
export default {
name: `SignUpForm`,
data() {
return {
signUpData: {
email: ``,
password: ``,
confirmPassword: ``
}
}
},
methods: {
onEmailSignUp() {
// Here this is component
console.log(this.$refs)
firebaseInstance.auth().fetchSignInMethodsForEmail(this.signUpData.email)
.then((response) => {
// other logic
} else {
// Here this is lost and equals undefined
this.$refs.email.setCustomValidity(`error`)
}
})
}
}
}

Answer 1

The bind instruction should be used on a function object, not on a function return value.
By doing
firebaseInstance.auth().fetchSignInMethodsForEmail(this.signUpData.email)
.then((response) => {
... all logic
}).bind(this)
You try to use bind on the return of the then method of you promise, which is a promise object and can't use bind.
You can try firebaseInstance.auth().fetchSignInMethodsForEmail(this.signUpData.email)
.then(function(response){
... all logic
}.bind(this))
instead. Here the bind is put on the function send in the promise so it should work correctly. I also transformed the function from arrow function to normal, because I think there is no need for arrow function with bind.

Answer 2

Using ES8 async/await sugar syntax you can do it like this :
async onEmailSignUp () {
try {
const response = await firebaseInstance.auth().fetchSignInMethodsForEmail(this.signUpData.email)
// other logic
} catch (error) {
console.log(error)
this.$refs.email.setCustomValidity(`error`)
}
}