Learn Apollo, Jest and Tweenlite

In this collection, we build a minimal flashcard application using React, primarily focusing on function components and the hooks API. To make sure we can understand and maintain existing code, there are also a few lessons toward the end that use class components so you can get familiar with the syntax. We cover important React concepts, and sprinkle in libraries that are pretty standard in the ecosystem like @reach/router, Jest, and React testing library. We start with create-react-app so we can get right into it without worrying about configuring tooling. There's [a separate course for that here](https://egghead.io/courses/modern-javascript-tooling-with-react?af=5mx0ie)

jest

Build a React App with the Hooks API

GraphQL is a fan favorite for good reason. It lets a client make specific, complex, and/or aggregate queries for data, and it’s user-friendly to boot.

If you’ve been meaning to learn GraphQL and start harnessing its powers, this is a great place to start.

This course is for GraphQL newbies with a basic understanding of React. It focuses on the client-side implementation of GraphQL usage using the Apollo client.

We’ll start with a guide on how to add the Apollo client to an existing project, then move on using the Query and Mutation components to fetch and manipulate data using a GraphQL API.

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

GraphQL Data in React with Apollo Client

In this course we are going to work through properly setting up Enzyme with Jest to test rendered components. This includes the nitty gritty of making our testing environment work with various versions of React. After we get our environment setup ready, we’ll work through the different ways we can render a component within our test pages. With a rendered component we can now test component methods and properties to assert that they are what is intended. 

Test React Components with Enzyme and Jest

End-to-end testing assures you of a few things: that all the integrated pieces of an application properly function, all those pieces work together as expected, and your tests include and simulate real-user scenarios — something unit and integration tests just don't do.

This course introduces you to two great tools for E2E testing: 

* Puppeteer opens and runs applications in a Chromium browser and performs the actions it's given.
* Jest asserts that the integrated pieces work as expected and that add-on libraries like Faker and pixelmatch take our tests to the next level.

Over 9 lessons, we will create common application features and use Puppeteer and Jest to run different types of tests against them. You'll get practice using these tools to render content, mimic user activity, automate tests, and measure the overall performance of your application.

End to End Testing with Google's Puppeteer and Jest

Here are all the Egghead.io lessons about testing with Jest! http://facebook.github.io/jest (https://kcd.im/egghead-jest)

Testing JavaScript with Jest

Apollo provides a universal GraphQL API on top of your existing services, so you can build new application features fast without waiting on backend changes.

apollo

Created by the team at Prisma, graphql-request is a lightweight package that can be used to send queries to any GraphQL API. Sending a request with graphql-request uses less syntax than a fetch request. In this lesson, we will query the totalDays field using this helper package.

Query a GraphQL API with graphql-request

To query a GraphQL API, all you need to do is send an HTTP request that includes the query operation in the body of the request. In this lesson, we will use the browser’s fetch method to request the total days skied from our GraphQL API.

Fetch Data from a GraphQL API

Apollo Server is a GraphQL server that listens for incoming HTTP requests on a single endpoint.  In this lesson, we will stand up a simple GraphQL service that handles a query for total days skied during a season.

Create a GraphQL API with Apollo Server 2.0

Apollo Client allows you to build performant, production-ready applications that consume data from GraphQL services. In this lesson, we will query the totalDays field using Apollo Client.

Send a GraphQL Query with Apollo Client

React Apollo is a component library that we can use to rapidly build GraphQL client applications with React. In this lesson, we get our React app ready by setting up the Apollo Provider and sending our query using the Query component.

Set Up a React GraphQL Client Application with react-apollo

The Query component is used to render the state of the network request along with the data that is returned from the GraphQL API. In this lesson, we will refactor our application to include an App component that displays the resulting count returned by the totalDays field.

Display Query Results using the Query Component 

We can read data from and write data to the cache directly with Apollo Client. In this video, we’ll update the UI by interacting with the cache instead of sending an additional request to the GraphQL server.

Update the Apollo Local Cache with the readQuery and writeQuery Methods

Queries get data from GraphQL services. If we want to change data, we will use GraphQL mutations. In this lesson, we’ll look at how to design GraphQL mutations to increment or decrement the number of ski days on record.

Change Data with GraphQL Mutations

Apollo Client comes with a local cache. The cache is where Apollo Client saves query results. You can read directly from or write directly to the cache which will allow you to reduce the number of network requests that your application makes. In this lesson, we will write the mutation results directly to the cache using the writeQuery method.

Update the Local Apollo Cache after a Mutation Using writeQuery

Using the GraphQL Schema Definition Language, we can define types that reflect all of the objects available on our API. In this lesson, we will create a SkiDay type and return a list of SkiDay objects with an allDays query. We will also create an enum, which describes a restricted list of allowed values for a particular field.

Create a GraphQL Object Type and Query a List of Objects

The addDay mutation should add details about each ski day. In this lesson, we’ll capture argument values from the GraphQL mutation and use this to change the ski day array.

Add Data to an Array with a GraphQL Mutation

Resolvers are functions that return data for specific fields. In this lesson, we’ll take a look at how to throw errors within resolvers if the data passed as arguments is incorrect or insufficient.

Incorporate Custom Error Handling within GraphQL Resolvers

GraphQL has five built-in scalar types that can be returned from a field: Int, Float, Boolean, String, and ID. It is also possible to create and validate your own custom scalar if you want to return a single value or leaf instead of an object from a field. In this lesson, we’ll build a custom scalar type to handle parsing and serializing dates.

Define a Custom Scalar Type for a GraphQL API

If you want to be able to parse and serialize custom scalar types sent as arguments, you’ll add the parseValue and parseLiteral functions to the custom scalar constructor. In this video, we’ll take a closer look at these functions and how they can be used to transform data passed by the client.


Parsing GraphQL Mutation Arguments with Custom Scalars

When passing arguments to a GraphQL mutation, you can send them inline, or you can wrap them in an input type. In this lesson, we’ll create an input type for the addDay mutation which will allow us to pass an entire object as an argument.

Wrap GraphQL Mutation Arguments with a GraphQL Input Type

GraphQL mutations are used to change data and can be also used to delete data. In this lesson, we’ll make changes to the removeDay mutation to delete a day from the ski days array by id. Additionally, we’ll return a custom type when we send the mutation.

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