Learn Chai, Purescript and React-storybook

PureScript is a small strongly, statically typed language inspired by Haskell and compiles to JavaScript. This means no run-time errors, human readable output, ADTs, and pattern matching (and more!) all at your fingertips.

In this course we will use an [online editor](http://try.purescript.org/) to show basics into PureScript with an instant visual representation, investigate the type system and ways to reason about common programing problems with PureScript. 

As we explore the type system and common problems that are faced when programming in PureScript we will learn plenty of functional programming concepts as PureScript is a purely functional language.

PureScript is a small strongly typed programming language that compiles to JavaScript.

purescript

Functional Programming Concepts in Purescript

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.

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Storybook is a UI component development environment for React, Vue, and Angular. With that, you can develop UI components without running your app.

Here I show how best to configure a React Storybook to use [Typescript](/q/typescript) (with TSX). This lets you write your reusable components with maximal type safety. Please see the provided code for the full source.

Configure React Storybook for use with Typescript

In this lesson, we'll see how we can get JSON decoding for free in PureScript using the Simple-JSON library. Because PureScript is a pretty powerful language, we can just declare what type we want the result to go into and get it for free!

Effortless JSON decoding with PureScript-Simple-JSON

[Storybook](https://storybook.js.org/) is a framework that allows you to develop components in isolation. It is ideal for a variety of use cases, most commonly when you're building some shared component toolkit. As such, Nx comes with a dedicated package `@nrwl/storybook` that adds a series of useful code generators to add storybook to an existing React library, but also to automatically generate stories and more.

Use Storybook to Develop React Components in Nx

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

javascript

[Nx](https://nx.dev) combines a lot of the best tools on the market, integrates them, and provides tooling to provide the best possible developer experience. One such pair is [Cypress](https://www.cypress.io/) and [Storybook](https://storybook.js.org/). Storybook allows developing components in isolation, which is also a great basis for testing components, which is where Cypress shines.
In this lesson, we're exploring some of the `@nrwl/storybook` code generation utilities that allow you to not only configure Storybook for a React application but automatically also set up a Cypress test configuration for it along with some spec files generated from the Storybook stories.

Use Cypress and Storybook to test your React Components in Isolation

In this lesson, we show how to setup React Storybook into an existing React project. We’ll go through common configuration files and how to adjust them.

Add React Storybook to a Project 

Components trigger actions via function props to notify of events that occur within the Component. We can inspect those events using React Storybook.

Inspect Component Events with React Storybook

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

chai

[Chai](https://npmjs.com/package/chai) assertions work great with the [Mocha](https://npmjs.com/package/mocha) testing framework. In this lesson we'll walk through out to install Chai and [karma-chai](https://npmjs.com/package/karma-chai) so you can use the `expect` assertions in your tests.

Use Chai assertions for tests in a Karma project

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.

mocha

Every dependable library needs to have tests to ensure that you don't push accidental bugs. In this lesson, see how you can set up mocha and chai to start testing your library.

Setting up Unit Testing with Mocha and Chai

Now that you've got everything set up with mocha and chai, it's time to actually write tests. In this lesson you'll learn how to use `describe` and `it` to outline your tests and make sure you don't break your library in the future.

Unit Testing with Mocha and Chai



[React Storybook](https://github.com/kadirahq/react-storybook) is a UI component development environment for React.
With that, you can develop UI components without running your app.

Here I show how to get started with React Storybook.
For more information, have a look at our [documentation](https://getstorybook.io/docs).

Getting Started with React Storybook

React Component stories can be dynamically loaded into React Storybook instead of doing it manually every time.

Load React Storybook Stories Dynamically

In this lesson, we will use Chai's request method to test our Node application's API responses.
By the end of this lesson, you will know how to:
- install the prerequisites to use mocha and chai in your application
- test for HTTP status response codes
- test for a string of text on a page
- test for a json response and validate the properties of the object
- write tests that not only verify the response of your application, but the behavior as well


Test Node RESTful API with Mocha and Chai

Writing great ES6 style Promises for Node.js is only half the battle. Your great modules must include tests as well to ensure future iterations don't break them. In this lesson, I show you a simple ES6 Promise in Node.js, then walk you through creating tests in Mocha using chai and chai-as-promised to test both resolve and reject methods.

Testing ES6 Promises in Node.js using Mocha and Chai

Story is the smallest unit of React Storybook. A story describes a React Component, and its various states and variations. Stories can describe complex components with dynamic properties and data loaded from a service. In this lesson we will write our first React Storybook story.

Write the First React Storybook Story

In this lesson, you will learn how to verify your API server is returning HTTP 400 responses when clients submit incorrect data. Returning HTTP 400 ensures that your clients are notified of the incorrect usage. Testing for them ensures your API returns errors instead of incorrect responses when supplied with incorrect data.

Test for HTTP 400 responses with Mocha and Chai

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

Storybook is a UI component development environment for React, Vue, and Angular. With that, you can develop UI components without running your app.

Here I show how to set up Storybook to display React components from scratch.

Set up Storybook for React from Scratch

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.

In this lesson we'll go through the process of setting up Storybook for Vue. We'll use Vue CLI to create a new Vue application and Storybook CLI to setup some initial stories and config. Storybook can help you develop UI components in an isolated area without running your full application.

*Additional Resources*
https://medium.com/storybookjs/introducing-storybook-for-vue-940f222541c5
https://storybook.js.org/basics/guide-vue/

 Getting Started With Storybook for Vue

Storybook is a UI component development environment for React, Vue, and Angular. With that, you can develop UI components without running your app.

Here I show the best configuration for React Storybook, and walk through adding your very first React Component and Story to your Storybook.

Add your first React Story to Storybook

Storybook is a UI component development environment for React, Vue, and Angular. With that, you can develop UI components without running your app.

Here I show how to add a landing/welcome page to your Storybook, so that first-time viewers get to read a message from you or have some orientation around the structure of the Storybook you are building. We also introduce the idea of sequential additions to your Storybook config so you can get a sense of how to modify it for your own needs.

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