Firebase Cloud Firestore doc.data().includes or .IndexOf doesn't work

Question

I am trying to work with an array, trying to run doc.data().includes and doc.data().indexOf on the array I stored on the cloud firestore, the array is the only thing that exists in the doc.

The data is arranged like this

    0: example@gmail.com
    1: firebase@gmail.com
    2: new@gmail.com

To get to the data I just do

firebase.firestore().collection('mails').doc('emails').get().then((doc) => {
            if (doc.exists) {
                console.log(doc.data()); //prints the list of emails in form of array
                doc.data().IndexOf(email); //error IndexOf doesn't exist
                doc.data().includes(email); //error includesOf doesn't exist
            }
            else {
                console.log('data doesn't exist');

            }

        });

Answer 1

To Get Access to doc.data().IndexOf or doc.data().includes or any other array related functions, just convert the doc.data() to array like this:

var docArray = Object.values(doc.data());
docArray.includes(stringToSearchFor);

or

Object.values(doc.data()).includes(stringToSearchFor);

this will allow you to run docArray.includes and docArray.IndexOf . Reason for converting is that firebase returns the entire doc which is an object of objects, you can see this by console.log(doc.data()) and seeing prototype field. This happens because firestore stores the array a json object meaning the array index numbers you see are not actually index numbers, they just object keys.

meaning

0: example@gmail.com
1: firebase@gmail.com
2: new@gmail.com

where 0, 1, 2 is the index( or as it seems) and example@gmail.com, firebase@gmail.com, new@gmail.com is value but in firestore that 0, 1, 2 is actually just keys, they are not index. So to get either the key(the numbers) or the values( the emails) we just run Object.keys(doc.data())// will return numbers or Object.values(doc.data())//will return emails and you will get array that you want and now you can run operations on this array.

Answer 2

I would suggest that you store your data in an Array and not as separate fields as shown by your Firestore database screenshot.

Your Firestore document currently contains 6 different fields and with doc.data() you retrieve all the 6 fields in this document as one JavaScript Object: this is why the Array methods cannot work. If you store this data in one Array (ie one field of type Array) it will be ok.

You can try the following code:

  const docRef = firebase.firestore().collection('mails').doc('emails');

  docRef
    .set({
      mails: ['example@gmail.com', 'firebase@gmail.com', 'new@gmail.com'],
    })
    .then(() => {
      return docRef.get();
    })
    .then((doc) => {
      if (doc.exists) {
        const email = 'example@gmail.com';
        console.log(doc.data().mails); 
        console.log(doc.data().mails.indexOf(email)); 
        console.log(doc.data().mails.includes(email)); 
      }
    });