1. Feature Overview

👋 Welcome to Lift-off IV!

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Lift-off IV: Mutations is a certifying course!

By completing this course, you're getting one step closer to earning your Graph Developer - Associate Certification.

Good to see you here for Lift-off Part IV! We've been hard at work on our Catstronauts app, diving into GraphQL 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 GraphQL mutations.

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 mutations, learning best practices for our mutation responses. We'll write our resolvers 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 GraphQL server.

Ignition sequence...


Our app uses Node.js on the backend and React on the frontend. 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

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
┃ ┣ 📄 README.md
┃ ┣ 📄 package.json
┣ 📂 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.

Note: The examples in this course use npm, but you're welcome to use yarn if you prefer.

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

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 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 Apollo Sandbox. The Explorer is free to use, and it provides awesome development features like interactive query building, query history, and response hints. This will make building our queries fast and fun.

To open the Explorer in Apollo Sandbox, 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.

In the browser, we can see that our server is running successfully, with a message inviting us to query it. Let's click Query your server to see our graph in action with Apollo Sandbox.


Let's get to it!