Author avatar

Gaurav Singhal

Using React Router with CDN Links

Gaurav Singhal

  • Nov 7, 2020
  • 6 Min read
  • 23,983 Views
  • Nov 7, 2020
  • 6 Min read
  • 23,983 Views
Web Development
Client-side Frameworks
React
Front End Web Development
Introduction

Introduction

When you are learning a new library or exploring new concepts in development mode, using CDNs can come in handy as they require minimal setup and get you up and running with only a few lines of code. To learn and explore React Router as a beginner, you can use a simple CDN setup without the hefty webpack configuration. In this guide, you'll learn how to use React and React Router using CDN links.

Setting up

Create a new file called index.html with the following boilerplate.

1<!DOCTYPE html>
2<html>
3  <head>
4    <meta charset='UTF-8'>
5  </head>
6  <body>
7    <div id='root'></div>
8    <script type='text/babel'>
9
10    </script>
11  </body>
12</html>
html

The <div> inside the <body> is where your React App's DOM goes. The <script> following the <body> is where you can write your regular JavaScript to React. Next, include the CDN links as scripts for React, ReactDOM, React-Router-DOM, and Babel, as shown below

1 <head>
2    <meta charset='UTF-8'>
3    <script src='https://unpkg.com/[email protected]/umd/react.production.min.js'></script>
4    <script src='https://unpkg.com/[email protected]/umd/react-dom.production.min.js'>    </script>
5    <script src='https://unpkg.com/[email protected]/umd/react-router-dom.min.js'></script>
6    <script src='https://unpkg.com/[email protected]/babel.js'></script>
7  </head>
html

Now you are ready to use React and React-Router-DOM inside this HTML file.

Importing React Router Elements

React Router offers components such as HashRouter, Route, Link, and so on for different purposes. Inside a regular React-CLI (Create-React-App) project, install react-router-dom as a dependency and import the components, as shown below.

1import {Route,Link, HashRouter} from 'react-router-dom';
javascript

However, inside a regular JavaScript file, you need to call these components as properties of the ReactRouterDOM global object available via the CDN (React-Router-DOM's script) and assign it to a variable to use it. So in order to use the Link and Route components, you need to do the following:

1const Link = ReactRouterDOM.Link;
2const Route = ReactRouterDOM.Route;
javascript

Creating the App Component

Let's create a simple hooks component, the App Component, as shown below, and render it on the DOM.

1 const App = () => (
2       
3 )
4ReactDOM.render(<App />, document.querySelector('#root'));
javascript

Next, add a few links inside this component. 

1const App = () => (
2        <ReactRouterDOM.HashRouter>
3          <ul>
4            <li><Link to="/">Home</Link></li>
5            <li><Link to="/login">Login</Link></li>
6            <li><Link to="/register">Register</Link></li>
7          </ul>
8        </ReactRouterDOM.HashRouter>
9)
javascript

The HashRouter component is directly invoked from the ReactRouterDOM global object. This is another method of requiring React-Router-DOM components, in addition to the method shown in the previous section.

Finally, set up some simple routes, as shown below.

1 <Route path="/" exact component={Home} />
2 <Route path="/login" component={Login} />
3 <Route path="/register" component={Register} />
javascript

Creating Child Components

On requesting the route /login, the Route component renders the Login Component. Create these child components to show a different message every time their route is requested.

1 const Home = () => <h1>Home</h1>
2 const Login = () => <h1>Login</h1>
3 const Register = () => <h1>Register</h1>
javascript

Run this HTML file and click on the login link. The current route changes to /login instead of / and the Login component is rendered. Similarly, the Register component can be rendered by clicking on the register link.

Have a look at the entire index.html file below.

1<!DOCTYPE html>
2<html>
3  <head>
4    <meta charset='UTF-8'>
5    <script src='https://unpkg.com/[email protected]/umd/react.production.min.js'></script>
6    <script src='https://unpkg.com/[email protected]/umd/react-dom.production.min.js'></script>
7    <script src='https://unpkg.com/[email protected]/umd/react-router-dom.min.js'></script>
8    <script src='https://unpkg.com/[email protected]/babel.js'></script>
9  </head>
10  <body>
11    <div id='root'></div>
12    <script type='text/babel'>
13      const Link = ReactRouterDOM.Link;
14      const Route = ReactRouterDOM.Route;
15
16      const App = () => (
17        <ReactRouterDOM.HashRouter>
18          <ul>
19            <li><Link to="/">Home</Link></li>
20            <li><Link to="/login">Login</Link></li>
21            <li><Link to="/register">Register</Link></li>
22          </ul>
23
24          <Route path="/" exact component={Home} />
25          <Route path="/login" component={Login} />
26          <Route path="/register" component={Register} />
27        </ReactRouterDOM.HashRouter>
28      )
29
30      const Home = () => <h1>Home</h1>
31      const Login = () => <h1>Login</h1>
32      const Register = () => <h1>Register</h1>
33
34      ReactDOM.render(<App />, document.querySelector('#root'));
35    </script>
36  </body>
37</html>
html

Conclusion

Using CDNs for development offers a faster development environment where you can explore and experiment according to your needs. It also comes in handy when you are developing only a backend app by serving HTML files so you don't need to separately set up a frontend project consuming it. You can explore large React Libraries like Redux via CDN first to save time, and then use them inside your Create-React-App project. If you have any queries, feel free to contact me at CodeAlphabet.

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