📓 Updating and Deleting Tickets in Firestore

We're ready to get our edit and delete functionality working again. We will continue to refactor code in TicketControl.js to update the edit and delete functionality to alter tickets directly in Firestore. We'll also make use of three Firestore functions:

• updateDoc() will allow us to update a document in Firestore.
• deleteDoc() will allow us to delete documents in Firestore.
• doc() will allow us to reference a document in the firestore database. With doc(), we can specify the location of a new document or the location of an existing document.

Updating Tickets

---

To update tickets in Firestore, we'll refactor the handleEditingTicketInList() function in the TicketControl component.

First, we need to import updateDoc and doc from firebase/firestore:

src/components/TicketControl.js

import { collection, addDoc, onSnapshot, doc, updateDoc } from "firebase/firestore";

Next, we need to refactor the handleEditingTicketInList() function. Here's the new code:

src/components/TicketControl.js

...
import { collection, addDoc, onSnapshot, doc, updateDoc } from "firebase/firestore";
import db from './../firebase.js'

function TicketControl() {
  ...

  const handleEditingTicketInList = async (ticketToEdit) => {
    const ticketRef = doc(db, "tickets", ticketToEdit.id);
    await updateDoc(ticketRef, ticketToEdit);
    setEditing(false);
    setSelectedTicket(null);
  }

  ...

  return (
    ...
  );
}

export default TicketControl;

While this code is new, it's rather similar to the process we followed when adding a ticket to Firestore:

• First, we create a document reference with the doc() function for the ticket that we want to update:
  • The doc() function takes 3 arguments: the database instance, the collection name, and the unique document identifier.
  • The doc() function returns a DocumentReference object, which as its name suggests, is an object that acts as a reference to a document within our Firestore database.
• Next, we call the updateDoc() function. The first argument we pass into this function is the document reference for the ticket we want to update, and the second argument is the new data that the ticket should be updated with.
• Finally, take note that the updateDoc() function is asynchronous, so we need to make our handleEditingTicketInList() function async and apply the await keyword before the updateDoc() function call.

Note that we can optionally rewrite the above function like so:

const handleEditingTicketInList = async (ticketToEdit) => {
  await updateDoc(doc(db, "tickets", ticketToEdit.id), ticketToEdit);
  setEditing(false);
  setSelectedTicket(null);
}

Since we've set up the listener in the last lesson, this means that anytime we update a ticket with the updateDoc() function, our listener will be triggered and the mainTicketList state variable in the TicketControl component will be updated.

Deleting Tickets

---

To delete documents in Firestore, we'll update the handleDeletingTicket() function in the TicketControl component. We'll also need the Firestore function deleteDoc(), so let's start by updating our import statement from firebase/firestore:

src/components/TicketControl.js

import { collection, addDoc, onSnapshot, doc, updateDoc, deleteDoc } from "firebase/firestore";

Next, let's update handleDeletingTicket(). Here's the new code:

src/components/TicketControl.js

...
import { collection, addDoc, onSnapshot, doc, updateDoc, deleteDoc } from "firebase/firestore";
import db from './../firebase.js'

function TicketControl() {
  ...

  const handleDeletingTicket = async (id) => {
    await deleteDoc(doc(db, "tickets", id));
    setSelectedTicket(null);
  } 

  ...

  return (
    ...
  );
}

export default TicketControl;

The deleteDoc() function is nearly identical to the updateDoc() function:

• It's asynchronous and uses async and await to manage the asynchrony.
• It takes a document reference as an argument that specifies which document in the Firestore database should be deleted.

The only difference from the updateDoc() function is that deleteDoc() does not take a second argument for data.

And with that, we've completed CRUD functionality for our Help Queue application!

What's Next

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In the next lesson, we'll wrap up our introduction to Firestore by reviewing how to structure data in Firestore.

In upcoming coursework, we'll expand the functionality of our Help Queue:

• We'll add authentication and basic authorization.
• We'll use the react-router library to create routes.
• We'll host our project with Firebase.
• We'll learn about Firestore Queries, styled components, and other further exploration opportunities.
• Finally, we'll incorporate a wait time into our Help Queue.