Learn Apollo, Jest and Ruby

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 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

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

Most developers would raise an eyebrow if they saw database queries being done in a for-loop, but GraphQL provides just enough abstraction that it isn't always intuitive exactly how many times each resolver fires at scale, nor is it obvious how to batch operations efficiently and still return the correct results to the correct consumer.

You'll learn how to use the GraphQL Data Loader pattern to improve the performance of your application, and solve scaling issues before they become a problem.

To do this, we'll first implement our own naive version of the pattern to understand why the API is shaped how it is. Then we will switch over to the official DataLoader package and explore the benefits further.

## Skills you'll Gain

- Implement a cache layer to optimize your requests
- Batch requests so your Database isn't overloaded
- Build a performant GraphQL API

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

Use GraphQL Data Loaders to Prevent Scaling Issues by Batching & Caching Database Requests

At the core of a good client-side GraphQL library is a cache. The cache is very important for improving the efficiency of your data retrieval and providing your users with a clean user experience.

In this course, we're going to see how Apollo's powerful cache helps easily solve complex UI problems, such as pagination, handling loading and error states, optimistic updates, and minimizing network requests.

We'll start from the basics, and look at how to make queries and mutations, but then we'll look at how the cache is behind most of Apollo's immediate benefits. We'll explore in-depth how it works, how it stores data, and how we can manually modify it manually for advanced scenarios.

Even if your backend doesn't fully support GraphQL yet, we'll look at how to write GraphQL queries in your components that retrieve local client state under the hood - or that can even make REST API calls.

Manage State in React Apps with Apollo Client and GraphQL

Best practices for building & testing redux applications have changed dramatically over time. This course aims to be a comprehensive and up-to-date resource for those seeking to confidently test their redux apps. Whether you're just getting started or want to improve on your existing testing strategy, there will be something in this course for you.

This first few lessons of this course look at how to add jest to an existing react/redux application that was built on top of [vite](https://vitejs.dev/). We cover basic functionality like using `npm test` vs `npx jest` and generating and using [code coverage](https://jestjs.io/docs/cli#--coverageboolean) to inform our testing strategy.

The next 10 or so lessons cover the specifics of unit testing the redux code in our application. We'll go over how to test reducers, selectors and thunks. As part of this we'll touch on mocking APIs and using [Redux Mock Store](https://github.com/reduxjs/redux-mock-store) as well as running actions through our applications' actual reducers to broaden our test coverage.

In the final part of this course we'll look at how we can test our redux connected react components using the various utilities that come with the [React Testing Library](https://testing-library.com/docs/react-testing-library/intro/). We'll cover simulating various kinds of user input with the [User Event Module](https://testing-library.com/docs/ecosystem-user-event), populating our redux store with test data, using [jest spies](https://jestjs.io/docs/jest-object#jestspyonobject-methodname), how to wait for asynchronous tasks to complete, and several approaches for finding & asserting that visual elements exist on the page.

This course is built on top of content that was created for the [Modern Redux with RTK and TypeScript](https://app.egghead.io/playlists/modern-redux-with-redux-toolkit-rtk-and-typescript-64f243c8) course and I highly recommend you start there if you haven't completed it already. It does expect a *basic* familiarity with react, redux and jest. TypeScript is used in these lessons, but is not a major focus and hopefully won't distract you too much if you prefer plain JavaScript.

No matter your experience level with redux and testing react applications, I'm confident your abilities will level up as you watch this course and follow along with the examples.

Thank you!

Confidently Testing Redux Applications with Jest & TypeScript

**Get started building dynamic apps with GraphQL and Vue3.**

As your app scales, so does the complexity of managing your routes and API endpoints. 

It gets tiresome. 

But this aspect of web development can be streamlined considerably! 

GraphQL is a powerful tool for querying and mutating your data. In this course, we are going to create a Vue3 app that leverages GraphQL to create a dynamic front end.

But what does GraphQL *do*? 

Its power comes from giving you a *single* endpoint that you make all your queries to. Instead of making a request to a specific endpoint and getting a fixed response, you can write flexible queries to a single endpoint.

![REST vs GraphQL diagram](https://res.cloudinary.com/dg3gyk0gu/image/upload/v1638989029/course-resources/create-a-graphql-powered-vue-3-application/rest_vs_graphql.png)

Vue3 has some great new features that we will be exploring, such as the setup script syntax. But you won't just be exploring Vue3's new features, we will be building a dynamic front end with an index, view pages generated from data, and forms.

To make our frontend dynamic, we will be powering it with GraphQL. We start with the basics by creating queries but we move on to more advanced topics such as query params, mutations, and pagination.

To actually use GraphQL in our Vue app we will be using the Vue Apollo Client. Which gives us convenient methods for making queries, getting the data back into the client, and handling errors.

## Gain These Skills

- Add GraphQL to a Vue 3 project
- Query and mutate data with GraphQL in Vue 3
- Create data-driven views with Apollo client
- Handle routing within a Vue 3 project
- Implement optimistic updates and infinite scroll

## Prerequisites

Some entry-level knowledge on Vue and GraphQL is recommended, but this course is beginner-friendly enough to where it isn't a strict requirement.

If you want to build a deeper foundation for both Vue and GraphQL we have a couple of awesome courses that you can hack through. 

For Vue, check out **[The Beginner's Guide to Vue 3](https://egghead.io/courses/the-beginner-s-guide-to-vue-3-1c46da8b),** which is also by Kevin. It's great for both newcomers to web dev and veterans alike. 

And for GraphQL, work through **[GraphQL Query Language](https://egghead.io/courses/graphql-query-language)** from Eve Porcello. Eve literally wrote the book on learning GraphQL and her course is similarly top quality. 

## What's Next?

Progressive Web Apps are a more advanced topic, and converting an existing Single Page **Vue** App into one makes for an excellent follow-up project. **->** [Offline-First Progressive Web Apps (PWA) in Vue.js](https://egghead.io/courses/offline-first-progressive-web-apps-pwa-in-vue-js)

If you want to take your **GraphQL** game to the next level, then becoming an expert in designing GraphQL schemas is the way to go. **->** [Designing GraphQL Schemas](https://egghead.io/courses/designing-graphql-schemas-99db)

And I know the following recommendation is a React course but *it really is that good*. You will learn some **advanced** techniques that will be applicable to Vue or any other Apollo compatible framework that you work with. **->** [Manage State in React Apps with Apollo Client and GraphQL](https://egghead.io/courses/manage-state-in-react-apps-with-apollo-client-and-graphql-a45b3b89)

Vue (pronounced /vjuː/, like view) is a progressive framework for building user interfaces. Unlike other monolithic frameworks, Vue is designed from the ground up to be incrementally adoptable. The core library is focused on the view layer only, and is very easy to pick up and integrate with other libraries or existing projects. On the other hand, Vue is also perfectly capable of powering sophisticated Single-Page Applications when used in combination with modern tooling and supporting libraries.

Create a GraphQL Powered Vue 3 Application

Kent walks us through the internals of dom-testing-library and react-testing-library. 

There is a lot of set-up and tear down when testing UI components. These two libraries take away a lot of the work required to test React components well. 

Jest is commonly used in tandem with react-testing-library to assert results of your components. Jest simulates most browser apis with jsdom. react-testing-library helps you get values out of your components the same way your end users will. 

Links from the show:
- [Testing Library](https://testing-library.com)
- [Testing Javascript](https://testingjavascript.com)
- [Unit vs Integration vs E2E](https://kentcdodds.com/blog/unit-vs-integration-vs-e2e-tests)
- [Why you shouldn't ReactDOM.render to the body](https://medium.com/@dan_abramov/two-weird-tricks-that-fix-react-7cf9bbdef375)
- [Effective Snapshot Testing]( https://kentcdodds.com/blog/effective-snapshot-testing/)
- [Dev Tips with Kent](https://youtu.be/ttmvAm6esSc)
- https://kcd.im/news

Understanding how react-testing-library works with Kent C. Dodds

Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.

rails

Expanding on [Part 1](https://egghead.io/lessons/angularjs-rails-todo-api-part-1), this lesson will look at how to bootstrap AngularJS in a rails application as part of the asset pipeline. With Angular available, you'll see how to communicate with the Rails API using $resource.

Rails Todo API Part 2

AngularJS is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications. Its goal is to augment web-based applications with model–view–controller (MVC) capability, in an effort to make both development and testing easier.

angularjs

Rails makes an excellent choice for delivering data to AngularJS via REST apis. In this first lesson of a two part series, you'll see how to create a simple API for CRUD operations on TODOs using Rails. This isn't an introduction to Rails, and assumes you know the basics. 

Rails Todo API Part 1

Jest is a painless JavaScript unit testing framework from Facebook. It is designed to be super easy to setup and is packed full of powerful features. In this lesson we see how easy it is to add to your TypeScript project. This will be followed by a quick example application.

Getting started with Jest using TypeScript

Create a search directive with AngularJS and Rails. You'll want to take a look at the related [Rails TODO API Part 1](https://egghead.io/lessons/angularjs-rails-todo-api-part-1) and [Rails TODO API Part 2](https://egghead.io/lessons/angularjs-rails-todo-api-part-2). This is **not** a Rails how-to, so some knowledge there is expected to get up and running.

Search Directive with Rails

React Storybook allows for easy snapshot testing integration with Facebook's Jest testing framework. Snapshot testing allows you to capture the state of your UI and then notify you when that UI has been altered. We can easily create and update snapshots with Storybook!
 




Jest Snapshot Testing with React Storybook

The reducer is at the center of how Redux manages state. In this lesson we’ll create a reducer function and see how Redux takes in state and actions and returns updated state. We’ll write and run unit tests using Jest to verify that our reducer function is working as expected.

Create a Redux-Style Reducer Function

In this lesson, I use Enzyme and Jest's Snapshot functionality to write an integration test for a component called CounterConsumer that consumes the Render Prop component Counter. This integration test is great because it doesn't necessarily care that CounterConsumer uses Counter behind the scenes, just that it works when integrated.

Other resources:
[Testing ⚛️ components using render props](https://blog.kentcdodds.com/testing-%EF%B8%8F-components-using-render-props-5623ab1814c)


Integration test a React component that consumes a Render Prop 

In this lesson, I use Enzyme and Jest to unit test a Counter Render Prop component. Writing integration tests are perfect for components that consume a Render Prop component. Likewise, unit tests are important to write for the Render Prop component itself, as you can test each individual unit that makes up the component.

Unit test a React Render Prop component

In order to get up and going with Enzyme and Jest, some configurations are required. We will need to install some babel plugins, create a specific package json script, and depending on which version of Jest, add Jest configurations to our package.json. 

Install Enzyme and Configure Jest

Within some of React’s releases there are major breaking changes that require different setups for Enzyme. In this lesson we are going to walk through how to setup your testing environment with some of these releases. 

Test Against Different React Releases with Enzyme

In this lesson we will shallow render a component and pass through different config options. Shallow rendering is useful to test components as individual units. This helps ensure that tests aren’t indirectly asserting on behavior of child components. We’ll also use the debug method to show how we can easily view our component for debugging purposes. 

Shallow Render a React Component with Enzyme

In this lesson I refactor a simple application built with Apollo, GraphQL, and React to utilize Apollo Boost. Apollo Boost combines many of the Apollo libraries we had to import and configure separately into one awesome API. 

Resources:

[What's in Apollo Boost](https://github.com/apollographql/apollo-client/tree/master/packages/apollo-boost#whats-in-apollo-boost)

[Zero config GraphQL State Management](https://dev-blog.apollodata.com/zero-config-graphql-state-management-27b1f1b3c2c3)


Zero-config Apollo + GraphQL with Apollo Boost

Once we have a shallowed rendered component, we can now test that the expected nodes rendered are correct. We will use Jest’s built in assertions as well as some Enzyme shallow render methods in our tests. The render methods include .find, .exists, .children, .hasClass, and .text. 

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