Firebase V9 Firestore DELETE Document Field Using updateDoc()

Using the updateDoc() method, you can delete one or more document field(s) in the Firebase Firestore Database.

• Delete A Document from a collection
• Delete A Field from a document → you’re here

Let’s say you want to delete the field called code from a sample Firestore document like below.

Import Firestore and d*e-structure* the four methods that we need to perform the delete operation to one or more document field(s).

• getDatabase()
• doc()
• updateDoc()
• deleteField()

import { getFirestore, doc, updateDoc, deleteField } from "firebase/firestore";

Then, initialize the Firestore database.

const db = getFirestore(app);

The updateDoc() method takes two arguments:

• doc()
• data {}

Doc()

The first argument of the updateDoc() method is doc().

The doc() method takes three arguments.

• database → db
• collection name → cities
• Document ID → yftq9RGp4jWNSyBZ1D6L (see the sample document screenshot above)

Call the doc() method with these arguments and assign it to a constant called docRef.

const docRef = doc(db, "cities", "yftq9RGp4jWNSyBZ1D6L");

Delete Field()

The second argument of the updateDoc() method is the JavaScript object with the field name(s) that you want to delete.

In this case: code

const data = {
  code: deleteField()
}

To delete a field from a Firestore document, call the deleteField() method as a value of it.

Call updateDoc() To Document Field

Invoke the updateDoc() method and pass docRef and data as arguments to it.

The updateDoc() method returns a promise so chain .then() and .catch() methods.

import {getFirestore, doc, updateDoc, deleteField} from "firebase/firestore";

const db = getFirestore();

const docRef = doc(db, "cities", "yftq9RGp4jWNSyBZ1D6L");

const data = {
    code: deleteField()
};

updateDoc(docRef, data)
.then(() => {
    console.log("Code Field has been deleted successfully");
})
.catch(() => {
    console.log(error);
})

When you run the updateDoc() query, the field name code **will be **removed from the Firestore document.

One more things it’s worth pointing out here is when you delete all the fields from a document, the document ID remains available in the collection and you can add a new field to the document.