Assignment 4

In this assignment we will be connecting to a database directly through our frontend!

Step 0 - Setup

Create a Next.js using our starter code with the following command:

yarn create next-app --typescript --example "https://github.com/cornell-dti/trends-sp22-starters/tree/main/a4" YOUR_DIR_NAME

Create a Firebase Project

For this assignment, you will be setting up your own Firebase project. You will be connecting your Next.js web app to the Firestore database to store task data.

See Ed for more specific Firebase setup instructions.

Step 1 - Finding One's Bearings

As with A2/A3, run yarn dev in the project directory to start the server and navigate to localhost:3000 to see what the starter code gives you.

In this assignment we will be implementing a simple task/todo list with add/delete functionality. Each task can also be "checked off" to denote being completed.

Tasks will be stored in our Firestore database, within a collection called tasks. Each document in the collection will represent a single task, containing information such as the text/name of the task, as well as whether is checked off.

Here are the important files you'll be working with:

• React Components
  • util/firebase.ts
    • Utility file for all Firebase-related exports.
    • We initialize the Firebase app here, so this is the place to paste your firebaseConfig.
  • components/frodo/Frodo.tsx
    • Overall "todo list" component.
    • We store a list of tasks in the state which gets passed down and displayed in children components.
  • components/frodo/TaskAddControl.tsx
    • Component for adding a new task to the task list.
    • Instead of updating state directly, we will perform a database operation in order to add a task.
  • components/frodo/TaskList.tsx
    • Simple "intermediate" component that maps over a list of tasks.
  • components/frodo/TaskItem.tsx
    • Component for displaying a task's information.
    • Has a toggleable checkbox and a "delete" button
• Other Files
  • types/index.ts
    • Task is a simple schema for a task. Firebase documents that represent tasks should match this schema.
    • TaskWithId is a type that has every property in Tasks PLUS the id property, which represents the task's Firebase document id.

As always, make sure to fill in all the TODOs before submitting!

You can press CTRL + SHIFT + F in VSCode to search through all project files.

Step 2 - Add The Firebase Config

In util/firebase.ts, you want to fill in your Firebase config with data found on the Firebase Console. To find the config, you can start at your Console and navigate Settings/Cog -> Project settings -> Scroll Down

You will find a code snippet including something that looks like the following:

const firebaseConfig = {
  apiKey: 'XXXXXXXXXXXXXXXXXXXXXX',
  authDomain: 'XXXXXXXXXXXXXXXXXXX.firebaseapp.com',
  projectId: 'XXXXXXXXXXXXXXXXXXX',
  storageBucket: 'XXXXXXXXXXXXXXXXXXX.appspot.com',
  messagingSenderId: 'XXXXXXXXXXXXXXX',
  appId: 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
};

Copy/replace the empty object in your project code in order to finish setting up your Firebase.

Step 3 - Fetching Data

If we look at components/frodo/Frodo.tsx, we see that there is a useState hook used to keep track of the tasks. However, we never call setTasks!

This web app should connect to our Firestore database to get all the tasks, and then set our local state to what the database gives us.

The plan is simple:

1. First, construct a Firebase query that gets all the documents in the tasks collection.
   • Hint: use query() and collection() to create the query
2. Then, subscribe to the query in order to get realtime updates to the query results
   • We use the onSnapshot() function from the Firebase library to do this
   • The code for this step is provided, you just have to uncomment it
3. Finally, set our tasks state with information contained in querySnapshot
   • Hint: use .map() to create a TaskWithId[] list
   • Hint 2: use obj as Task to "cast" an object to type Task
   • Hint 3: use doc.id to get the id of a document
   • Hint 4: use {...obj, foo: 'bar'} to create a new object based on obj, but with an additional property foo (this is object destructuring!)

Feel free to add in dummy Firestore documents through the web interface (Console) to check if you've completed this step properly.

Step 4 - Adding Tasks

Now let's direct our attention to components/frodo/TaskAddControl.tsx.

We have a function called addTask that fires whenever the form submits (such as when a user clicks the Add Task button).

All we have to do here is implement the rest of this function!

Hint: you can call the addDoc() function without specifying an id to create a document with a random id (in many cases this is preferable).

Step 5 - Modifying Tasks

Let's wrap up by implementing functionality in components/frodo/TaskItem.tsx.

We have two functions toggleTask and deleteTask that are empty.

toggleTask is triggered when a user clicks on the checkbox. It should toggle the checked status of that particular task.

deleteTask is triggered when a user clicks on the delete button. It should remove that particular task from the database.

You may find updateDoc and deleteDoc helpful for this part.

Step 6 - Submission

Make sure you've completed all of the TODOs, including your name/netid in components/layout/Footer.tsx and the hours worked in pages/index.tsx

Feel free to remove the contents of your firebaseConfig object in firebase.ts before submission. We will be grading by connecting your app to our own database.

Once you are done, please zip up everything in your project folder EXCEPT the node_modules and .next folders.

Then submit to CMS!