Learn Cypress, Leaflet and Serverless

Starting from a prebuilt frontend, Jason Lengstorf guides you through the creation of a "Corgi Up-boop App" that uses Netlify Functions and Hasura. You can view [the deployed final product on Netlify](https://egghead-serverless-functions.netlify.app/).

You'll set up the Netlify CLI, and configure a local development environment before writing and deploying functions with a few different use cases.

The first example function bypasses CORS restrictions to retrieve corgi data from an example third-party API.

Next, you'll configure environmental variables to securely communicate with the Unsplash API without exposing private keys to the client.

Serverless functions don't persist data by themselves, so we will use  Hasura to create a GraphQL API for tracking the number of "boops" each corgi receives.

This course is an excellent illustration of the speed of Serverless functions, and how fast you can implement functionality in your web applications.

An all-in-one workflow that combines global deployment, continuous integration, and automatic HTTPS.

netlify

Build a Corgi Up-boop Web App with Netlify Serverless Functions and Hasura

If you've ever worked on a website for a business, there's a good chance you've included a map.

A Google Map embed is sufficient for showing a location, but doesn't leave you many customization options.

React Leaflet to the rescue!

In this course, Colby Fayock will guide you through a series of lessons and challenges that will build your map making skills as you build out a web app for a fictional restaurant.

You'll get practice with handling API keys and using React Hooks to implement a custom interactive map complete with metadata and additional overlays.

This course has built-in challenges that you are encouraged to pause and work through, but feel free to just watch.

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

Build Maps with React Leaflet

In this collection, you'll learn the basics of creating a new map in your React application with React Leaflet. We'll walk through adding the map itself as well as adding markers with popups, different shapes, and increasingly complex features to your map!

Mapping with React Leaflet

Imagine the following.

You join a new project and after getting access to the repo you notice that there's no tests.

You decide to ask the team whether they are in different repo or something and unfortunately the answer is:

>We don't have any tests, we didn't have the time.

😐

In this collection we're going to learn how to add e2e tests with cypress.io to an existing React app in order to do two things:

- 🌟 Ensure that our app currently works as intended
- 🌟 Allow us to add features to it with a technique called "Cypress Driven Development" 

In less than 20 minutes we're going to go through:

- ⚡️Adding cypress.io setup to an existing project
- ⚡️Testing search functionality with `data-cy` properties
- ⚡️Using "Cypress Driven Development" to add a new feature to an app
- ⚡️Use Cypress UI to debug an API response
- ⚡️How to use `cy.only` and `cy.skip` in order for us to build our e2e test suite faster

and much more!

Fast, easy and reliable testing for anything that runs in a browser.

cypress

Add e2e tests with cypress to a React application

One of the most important — but most ignored — practices for web developers is performing end-to-end testing on applications before they go live into production. You know: making sure they work like they’re supposed to. But testing can be tedious, and definitely not fun.

In this course, Brett Cassette will show you how you can test all layers of your application stack, simultaneously, with Cypress. When you use Cypress, it’s like having a robot that uses your app the way a real user would. Cypress reports if things work the way you designed them to — and if they don’t — every step of the way. And it’s fun.

After completing this course, you’ll be ready to apply the same E2E testing principles to your own applications. Stop leaning on your QA department (if it exists) to stress-test your application, and ship your app knowing it’s ready. 


Test Production Ready Apps with Cypress

The tools available for unit testing have come a long way. While testing may never be “easy”, the available tools have certainly moved testing closer to the simple end of the spectrum. Full end to end testing hasn’t quite kept the same pace and as a result many applications are testing manually and often by users in production. Cypress provides a testing environment that makes end-to-end testing fast and reliable with a simple API that makes creating automated unit tests for your web applications a no-brainer.


End to End testing with Cypress

Create a serverless application and deploy it in under thirty minutes!

We'll be using Netlify, Vite, TypeScript, and React in our project. This stack synergizes extremely well for rapidly developing professional-quality applications. 

If you haven't heard of Vite, it's the French word for quick! It's also a build tool that consists of a dev-server and an extremely fast bundler. It makes for a rapid development loop.

As for the rest. Netlify makes hosting fast and easy with serverless functions and continuous deployment. React enables you to quickly create reusable components. And TypeScript helps you write cleaner code that is easier to refactor. 

So get started and learn how to use this stack in your own applications!

Create a TypeScript powered serverless React application

Web accessibility (also referred to as a11y) is the design and creation of websites that can be used by everyone. Accessibility support is necessary to allow assistive technology to interpret web pages.

React fully supports building accessible websites, often by using standard HTML techniques.

Erin Doyle is an expert in creating accessible React applications and has developed a course that will give you a concrete process for auditing react apps for accessibility. In this course, you will go through different tools and libraries to audit components in a React app.

Auditing React Apps for Accessibility 

Your app can react in various way on different network conditions. Cypress has a great toolset for setting up those conditions, which enable you to test your app thoroughly. That way you can ship your app with confidence.

Cypress’ .intercept() command is one of the most fun command to use. And it’s also one of the most useful.

Especially when you are done with all your happy paths and want to increase your test coverage with some edge cases.

These edge cases can mean different data, headers or server behavior. You can modify all of these, dynamically or with a static fixture prepared beforehand

Test network edge cases with cy.intercept() command in Cypress

Leaflet is the leading open-source JavaScript library for mobile-friendly interactive maps. Weighing just about 38 KB of JS, it has all the mapping features most developers ever need.

leaflet

Leaflet makes creating maps in the browser *dead simple*. With some HTML and 3 lines of JavaScript, we can quickly have a map displaying.

Get Started with LeafletJS Mapping

With a basic map in place we can add shapes, like US states. We will then see how to style the shapes to make a visually appealing map.

Adding Shapes to Maps with Leaflet and GeoJSON

Rendering GeoJSON data on a map and interacting via mouse over, mouse out, and click.

Interactive Leaflet Maps with GeoJSON data

Adding Cypress to a project is a simple npm install away. We won’t need any global dependencies beyond node and npm to get started with Cypress. In this lesson we’ll look at our existing application, add Cypress as a dev dependency with npm and fire it up for the first time to have a look around.

Add Cypress to an Existing Application with npm

In order to test our application, Cypress will need to visit it in the browser. In this lesson we’ll see how we can visit our application with Cypress and how to configure a baseUrl for Cypress to make that even easier.

Visit a page with Cypress

In this lesson, we’ll add tests that finds a focused input. We’ll use Chrome’s dev tools from inside the Cypress runner to inspect the element and update our test to verify that the expected element is focused. We’ll see how Cypress can be used to test drive our application by creating a failing test and updating our application code to make it pass.


Find and Test Focused Input with Chrome’s DevTools in Cypress

React based applications often use controlled inputs, meaning the input event leads to the application code setting the value of the very input we’re typing into. Since this moves the input setting behavior into the application code, we should have a test to guard against future changes that might break this behavior. In this lesson, we’ll use the Selector Playground feature in Cypress and create a test that enters text into an input and asserts that the value is the same as the entered text.

Test React’s Controlled Input with Cypress Selector Playground

A lot of our tests will share setup steps. Since Cypress is using Mocha under the hood, we can take advantage of existing features such as the ability to define a `beforeEach` block that runs before each of our tests. In this lesson we’ll refactor two tests that contain duplicate commands by moving that duplication into the `beforeEach` for our `describe` block.


Reduce Code Duplication in Cypress Tests with beforeEach

To keep our tests fast and easily repeatable, it makes sense to create many integration tests and fewer full end-to-end tests. In this lesson, we’ll see how to stub out network requests to create repeatable integration tests by ensuring our application runs in a known state for our tests.


Stub Network Requests in a Cypress Test

When creating integration tests with Cypress, we’ll often want to stub network requests that respond with large datasets. All of this mock data can lead to test code that is hard to read. In this lesson, we’ll see how to use fixtures to keep sample data in files and easily load it on demand in your tests.

Load Data from Test Fixtures in Cypress

When testing interactions that require asynchronous calls, we’ll need to wait on responses to make sure we’re asserting about the application state at the right time. With Cypress, we don’t have to use arbitrary time periods to wait. In this lesson, we’ll see how to use an alias for a network request and wait for it to complete without having to wait longer than required or guess at the duration.

Wait for XHR Responses in a Cypress Test

Cypress provides a straightforward API that allows you to define custom commands. In this lesson, we’ll take a series of Cypress commands and wrap them up in a single custom command so we can easily repeat these steps in multiple specs.