Book Image

React Key Concepts

By : Maximilian Schwarzmüller
Book Image

React Key Concepts

By: Maximilian Schwarzmüller

Overview of this book

As the most popular JavaScript library for building modern, interactive user interfaces, React is an in-demand framework that’ll bring real value to your career or next project. But like any technology, learning React can be tricky, and finding the right teacher can make things a whole lot easier. Maximilian Schwarzmüller is a bestselling instructor who has helped over two million students worldwide learn how to code, and his latest React video course (React — The Complete Guide) has over six hundred thousand students on Udemy. Max has written this quick-start reference to help you get to grips with the world of React programming. Simple explanations, relevant examples, and a clear, concise approach make this fast-paced guide the ideal resource for busy developers. This book distills the core concepts of React and draws together its key features with neat summaries, thus perfectly complementing other in-depth teaching resources. So, whether you've just finished Max’s React video course and are looking for a handy reference tool, or you've been using a variety of other learning materials and now need a single study guide to bring everything together, this is the ideal companion to support you through your next React projects. Plus, it's fully up to date for React 18, so you can be sure you’re ready to go with the latest version.
Table of Contents (16 chapters)

5. Rendering Lists & Conditional Content

Activity 5.1: Showing a Conditional Error Message

In this activity, you'll build a basic form that allows users to enter their email address. Upon form submission, the user input should be validated and invalid email addresses (for simplicity, here email addresses that contain no @ sign are being referred to here) should lead to an error message being shown below the form. When invalid email addresses are made valid, potentially visible error messages should be removed again.

Perform the following steps to complete this activity:

  1. Create a new React project and remove the default JSX code returned by the App component. Instead, return a <form> element that contains an <input> of type="text" (for the purpose of this activity, it should not be type="email" to make entering incorrect email addresses easier). Also add a <label> for the <input> and a <button> that submits the...