Book Image

Getting Started with React

By : Doel Sengupta, Manu Singhal, Danillo Corvalan
Book Image

Getting Started with React

By: Doel Sengupta, Manu Singhal, Danillo Corvalan

Overview of this book

ReactJS, popularly known as the V (view) of the MVC architecture, was developed by the Facebook and Instagram developers. It follows a unidirectional data flow, virtual DOM, and DOM difference that are generously leveraged in order to increase the performance of the UI. Getting Started with React will help you implement the Reactive paradigm to build stateless and asynchronous apps with React. We will begin with an overview of ReactJS and its evolution over the years, followed by building a simple React component. We will then build the same react component with JSX syntax to demystify its usage. You will see how to configure the Facebook Graph API, get your likes list, and render it using React. Following this, we will break the UI into components and you’ll learn how to establish communication between them and respond to users input/events in order to have the UI reflect their state. You’ll also get to grips with the ES6 syntaxes. Moving ahead, we will delve into the FLUX and its architecture, which is used to build client-side web applications and complements React’s composable view components by utilizing a unidirectional data flow. Towards the end, you’ll find out how to make your components reusable, and test and deploy them into a production environment. Finally, we’ll briefly touch on other topics such as React on the server side, Redux and some advanced concepts.
Table of Contents (18 chapters)
Getting Started with React
About the Authors
About the Reviewers

Testing in JavaScript using Chai and Mocha

As discussed earlier, in order to write test cases for the React code, we will be installing some testing libraries to run tests and write assertions. Let's walk through the setup for the Chai assertion library and the Mocha testing framework. We need to install the libraries with the help of npm.

In the terminal type:

npm i -D mocha chai


install shortform: i

devDependencies shortform: D (the package will be installed only in a development environment)

After the Chai and Mocha libraries are installed by the previously mentioned command, they can be found under the node_modules directory.

We need to add the Mocha and Chai entries in our package.json file.

Package.json code

  "name": "JSApp",
  "version": "1.0.0",
  "description": "Get random numbers",
  "main": "index.js",
  "scripts": {
    "test": "mocha test.js"
  "devDependencies": {
    "chai": "3.2.0",
    "mocha": "2.2.5"

According to