1. Feature Overview

👋 Welcome to Lift-off IV!

Good to see you here for Lift-off Part IV! We've been hard at work on our Catstronauts app, diving into on both the server and client side.

So far, we've only dealt with retrieving data from our API. Now it's time to switch gears and work on modifying our data with .

Each track in our app displays the number of times it's been viewed. We want to increment this number every time a user visits the track page from the homepage.

To do this, we'll update our schema to include , learning best practices for our mutation responses. We'll write our to handle both successful responses and errors. And lastly on the client-side, we'll use a React hook called useMutation to send our request to the .

Ignition sequence...


Our app uses Node.js on the backend and React on the frontend. We recommend using the latest version of Node.

This course can be completed stand-alone but builds on concepts previously covered in Lift-off part I, part II and part III.

Clone the repository

Note: This course is available in both JavaScript and TypeScript. Confirm your language of choice at the top of the lesson before continuing.

In the directory of your choice with your preferred terminal, clone the app's starter repository:

git clone https://github.com/apollographql/odyssey-lift-off-part4

Project structure

This repo picks up where Lift-off III left off. Our project is a full-stack app with the backend app in the server/ directory and the frontend app in the client/ directory.

You'll also find a final/ folder that contains the final state of the project once you've completed the course. Feel free to use it as a guide!

Here's the file structure:

📦 odyssey-lift-off-part4
┣ 📂 client
┃ ┣ 📂 public
┃ ┣ 📂 src
┃ ┣ 📄 index.html
┃ ┣ 📄 package.json
┃ ┣ 📄 README.md
┃ ┣ 📄 vite.config.js
┣ 📂 server
┃ ┣ 📂 src
┃ ┃ ┣ 📂 datasources
┃ ┃ ┃┣ 📄 track-api.js
┃ ┃ ┣ 📄 index.js
┃ ┃ ┣ 📄 schema.js
┃ ┃ ┣ 📄 resolvers.js
┃ ┣ 📄 README.md
┃ ┣ 📄 package.json
┣ 📂 final
┃ ┣ 📂 client
┃ ┣ 📂 server
┗ 📄 README.md

Now, open the repository in your favorite IDE.

Let's start with the server app.

In a terminal window, navigate to the repo's server directory and run the following to install dependencies and run the app:

npm install && npm start

Note: We recommend using the latest LTS version of Node. To check your Node version, run node -v.

If all goes well, you'll see the installation complete and a message in the console indicating that the server is running.


Next, the client app.

In a new terminal window, navigate to the repo's client directory and run the following to install dependencies and start the app:

npm install && npm start

The console should show a bunch of output and a link to the running app at, or localhost:3000. You can navigate to http://localhost:3000 in the browser and see our homepage, which shows multiple track cards.


Setting up the Explorer

To write our queries, we'll be using the Explorer page in . The Explorer is free to use, and it provides awesome development features like interactive building, query history, and response hints. This will make building our queries fast and fun.

To open the Explorer in , you can cmd+click on the URL in your terminal (from starting the server) to open it in your browser, or you can open it here: http://localhost:4000.


Let's get to it!


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