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
Credits
About the Authors
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Learning JSX and Gotchas


Now it's time to master JSX and learn some Gotchas. You're going to learn some basic concepts to build ReactJS UI components using JSX. It includes practices when writing expressions, conditions, and creating lists of components. It will also walk you through how JSX differs from HTML (because it's not HTML) in some aspects.

Expressions

Consider the following code:

var Clock = React.createClass({
  render: function () {
    var today = new Date();
    return <h1>The time is { today.toLocaleTimeString() }</h1>;
  }
});

React.render(<Clock />, document.body);

JSX understands the curly braces {} whenever you want to put JavaScript code within your presentation code.

In the next example, let's improve our Clock component by supporting greetings depending on what the time is.

In the highlighted code mentioned later, if the current hour is lesser than 4, it should return day, and if the hour is greater than 4 but less than 18, it should return night:

var GreetingsClock...