Our Example Dentist Website

What are the objectives?

After this workshop, developers will be able to:

• Introduce React Router into a project
• Describe how routing in React works
• Build some routes in a React app

We'll make an example Dentist website that has a Home page, a page that lists available Procedures and a page displaying Contact information. Each off these pages of content will be built into their own regular React component; then we'll create a unique URL route that leads to each component.

Here's how we'll route our Single Page Application.

URL Route	Component	Content Description
/	<Home>	A homepage with welcome text.
/procedures	<Procedures>	A list of all dentist procedures.
/contact	<Contact>	A page with an address, phone number, and email.

Remember, the URL routes are paths off our main website. We could put our website at any domain, like www.ourdentistwebsite.com or www.premiumdental.com, and the URL route paths would behave the same. Paths only care about what comes after the domain name.

Our routes say that if someone goes to ourdomain.com/ they will see our homepage with welcome text. The content of this page will all be defined in its own component in a file called home.js. If someone navigates to the URL ourdomain.com/contact then they'll see content with the business address, a phone number and an email. All of this content will be defined in a component called Contact in a file called contact.js.

You can see all of the final code and a live working copy of the site here:

Full Repo: https://github.com/geluso/react-router-simple-dentist-site

Live Site: https://react-router-dentist.herokuapp.com/

In Your Terminal

Remember to stop the React project you currently have running!

Now let's make the dentist project. In your terminal, type:

$ create-react-app dentist-website
$ cd dentist-website
$ npm start

Your browser should open to http://localhost:3000/ and you'll see the standard "Welcome to React" message with a fancy rotating atomic icon. create-react-app creates several files for us in a directory called src. Open the App.js file in your editor.

App.js contains our main application. You should see the basic HTML structure of the standard React starter page. Make sure the file is the same thing you're looking at in the browser by finding the text Welcome to React inside an <h2> element.

Change the text to say My First React Router App, save the file and make sure you see the changes automatically appear in your browser.

If it doesn't automatically refresh, then try to manually refresh the page. If you still don't see changes after a manual refresh then something could be wrong. Make sure you're editing the right file.

Pro tip:

It's a good idea to make simple, verifiable changes like this when you're first starting to make changes to a project. It's like a sanity check.

Make sure you can do simple things first. Don't start with complex things; many things can go wrong when you make complex changes. Prove to yourself the small changes work, and you'll save yourself headaches debugging large complex changes.

Installing React Router

Let's install React Router.

Hit ctrl-c to stop the running app, so that we can use the terminal!

Since React Router is a third-party library, we'll need to use to download React Router and save it as a dependency in our project.

In your Terminal, enter:

$ npm install react-router-dom

Create Custom Homepage

Let's start the app again. Put the command npm start in your terminal.

Let's get rid of the standard "Welcome to React" page and replace it with our own Dentist Website Homepage. Continue editing App.js. Gut most of the HTML contents, and delete the import statement for the logo.svg which we won't use.

The App.js file contains one component that our whole App will live inside of. Remember that React components have a render(){ ... } function that defines what the component will look like when it is rendered on the webpage.

Reminder! The render function alway has to return at most one top-level element. It's common to wrap everything in your component in a `div``to make sure you satisfy this constraint.

So...

I added one <h1> that says Dentist Website and added a paragraph with some short welcome text. My App.js file now looks like this. Save the file and go to your browser to make sure these changes show up.

App.js

import React, { Component } from 'react';
import './App.css';

class App extends Component {
  render() {
    return (
      <div>
        <h1>Dentist Website</h1>
        <p>
          Welcome to my dentist website.
        </p>
      </div>
    );
  }
}

export default App;

Good. Now we have a simple homepage set up. Let's move on to getting the rest of the content for our site set up.

Creating Our Homepage Component

We've been editing App.js, which defines one component for our entire application. So far our app manually shows just the homepage. Let's refactor this so the content of the homepage is moved into its own component called Home.

1. Create a new file called Home.js.
2. Copy and paste everything inside App.js into Home.js to use as a template for how to create a React component.
3. Delete the import statement for ./App.css.
4. Find everywhere the file says App and rename it to Home. This code used to create a component called App. Now we're rewriting it to instead create a component called Home.
5. Look at the render() { ... } function and verify that it's returning content that represents our homepage. It should just be the one top-level <div>, the <h1> and a <p> paragraph element (if you used the same content as we did). Great. We actually don't need to make any changes here! Now you have your Home component.
6. Go back to the App.js file and delete the <h1> and <p> tags where we used to have content written directly inside our App component. We don't need that written inside App any longer, because we just moved it all to the new Home component.
7. Instead, we need to call our new component. Put <Home></Home> inside the <div> in the App component. This tells the App component to render the Home component right there inside the div.

Note: We have been using <Home /> to call components. <Home></Home> is just a different syntax we're showing you so that if you see it elsewhere, you're familiar with it.

8. Let's try it out! Look at the browser and see if the homepage appears. Unfortunately, if you've been following along, it won't. You'll see an error, which should look like this:

It's not enough to simply create the Home.js file and create the Home component. We must also remember to import the component into the App.js file. Any components you want to use in a file need to first be imported into that file.

Your App.js and Home.js files should look like this after you've properly created and imported the Home component.

App.js

import React, { Component } from 'react';
import './App.css';
import Home from './Home';

class App extends Component {
  render() {
    return (
      <div>
        <Home></Home>
      </div>
    );
  }
}
export default App;

Home.js

import React, { Component } from 'react';

class Home extends Component {
  render() {
    return (
      <div>
        <h1>Dentist Website</h1>
        <p>
          Welcome to my dentist website.
        </p>
      </div>
    );
  }
}

export default Home;

Create Components for Procedures and Contact

The purpose of our site is to create several components that we can swap out as the main content of the main page of our application in order to create a modern Single Page Application. We'll create two more components, and then we'll start routing things up.

1. Create a new file called Procedures.js
2. Create a new file called Contact.js

The files were created using the same procedure we used to create the Home component using the App component as a template. Basically: create each file, change the name of the component to its new name, then replace the HTML in the render() { ... } function with custom content. Be sure to import each new component into App.js just like we did with the Home component.

You can put your own content to be rendered by each component if you'd like. Refer to these complete files in the finished repo to make sure you got everything correct:

https://github.com/geluso/react-router-simple-dentist-site/blob/master/src/procedures.js https://github.com/geluso/react-router-simple-dentist-site/blob/master/src/contact.js

Now that we have our components made, there's nothing stopping us from importing multiple components into our App.js. So now, we have:

App.js

import React, { Component } from 'react';
import './App.css';

import Home from './Home';
import Procedures from './Procedures';
import Contact from './Contact';

class App extends Component {
  render() {
    return (
      <div>
        <Home></Home>
        <Procedures></Procedures>
        <Contact></Contact>
      </div>
    );
  }
}

export default App;

Check yourself! You should see all of content for each of the pages all stacked on top of each other on the homepage. If you don't see content from all three of your components then something is wrong. You must fix this before continuing. Always: do simple things before doing complex things!

Displaying Pages Individually

Try manually deleting two of the three components so only one component is left on the page at a time. You should see your webpage update with just that component. This is effectively what React Router does. We can configure React Router so that it's aware of which component we want to show on the screen, and React Router will swap the components out so that only the correct one is shown at a time.

Now that we've proven to ourselves that we're able to show each of the components on the main page, it's time to hook them up to Router.

Creating Routes

Here's the general syntax for creating routes. React Router uses some of its own components to define how URLs are routed to your components and to create links to those routes. You must have one <Router> component that wraps itself around multiple <Route> components. Each <Route> component has two pieces:

• path - defining the URL path that leads to the component.
• component - defining what component users will see when they navigate to the path.

<Router>
  <div>
    <Route exact path="/" component={Home} />
    <Route path="/procedures" component={Procedures} />
    <Route path="/contact" component={Contact} />
  </div>
</Router>

There are three other important things to note here:

• This goes in place of your existing component calls of <Home /> or <Home></Home> (depending on which syntax you went for).

• The first route for the homepage at the root URL path / uses a special extra exact attribute before defining the path. The exact attribute means the component associated with the route will only be shown if users are at exactly that URL path. If you forget to include the exact keyword then when someone navigates to /contact they will actually see two components, because / is a partial match for /contact.

• Notice that all of the <Route> components are wrapped inside one <div>. Like render, the <Router> element requires that it only has one direct child element. If you don't wrap the routes with a <div>, the page will appear blank, and you'll have to open your JavaScript console to see that there's an error being logged to the console. Like so -

Pro tip: It's a good habit to check the console for errors whenever your app is not behaving as expected.

Import Statements

In order to use the React Router components, you'll need to import them. This import syntax allows us to grab several specific components out of the react-router-dom library at once. So far we've used Router and Route.

The Router component is actually called BrowserRouter inside the library package, but we'll use the as keyword to rename it to Router so it's easier to remember.

While we're here, we'll also import a third component, Link, which we'll get to in a minute.

import {
  BrowserRouter as Router,
  Route,
  Link
} from 'react-router-dom';

Fully Routed

Here's how the imports and all the components look like together for our dentist website:

App.js

import React, { Component } from 'react';
import './App.css';

import {
  BrowserRouter as Router,
  Route,
  Link
} from 'react-router-dom';

import Home from './Home';
import Procedures from './Procedures';
import Contact from './Contact';


class App extends Component {
  render() {
    return (
      <Router>
        <div>
          <Route exact path="/" component={Home} />
          <Route path="/procedures" component={Procedures} />
          <Route path="/contact" component={Contact} />
        </div>
      </Router>
    );
  }
}

export default App;

Navigate to the Routes

Now that everything is hooked up you can manually enter different URLs and see how your page appears. If you go to http://localhost:3000/, you should see just the homepage. If you go to http://localhost:3000/procedures, you should see just the procedures page. If you go to http://localhost:3000/contact, then you should see just the contact page.

Check it!

• Make sure that React Router is routing from each URL to the proper component correctly.
• Double check to make sure that the home page doesn't display at the same time as another component. If the homepage is shown while you're at the path to /procedures or /contact then you probably did not write the exact keyword when you defined the / Home route.

Debugging Common Errors

Let's intentionally make an error. Delete the exact keyword off the Home route. Navigate to the /procedures page and the /contact page again and see how the components are displayed. You should see the content of the homepage and the content for one of the other pages at the same time, with the home page on top.

Now add the exact keyword back to the home route and notice that the pages don't double up any more.

Two common errors:

1. If the page appears blank, open the JavaScript console to see if there are errors. Chances are you have a typo somewhere or forgot to make sure the <Router> only has one child element. Remember, wrap all of your <Route> components in one <div>.
2. If multiple components appear on the page at the same time there's something with how you've routed URLs. Make sure you use the exact keyword on the root path / and make sure there are no duplicate URL paths defined anywhere.

Adding a Nav Section

Great, now our site is up and running! We can manually type in URLs and see the different pages.

Although... users never really type URLs, do they? We should probably have links at the top of the page so we can just click on things. We could build this ourselves, but we don't have to! Remember that Link component we imported from React Router?

Just like links in HTML, we can wrap <Link> tags around whatever text that we want to display to the user to click on. The pieces of this are:

• <Link> - creates <a> tags and automatically integrates modern HTML5 browser history mechanics for the Single Page Application. It has one attribute:
• to - what path to navigate to when the user clicks the link

We'll add one <Link> component that leads to each of our different content pages.

<Link to="/">Go to Home Page</Link>
<Link to="/procedures">See Our Procedures</Link>
<Link to="/contact">Contact Us!</Link>

Did you notice that we don't reference components here? We simply make links for users to click that connect to URLs, and the Router section in the code handles the actual component changes.

We can include those links in a <nav> element at the top of our page. It will stay on the page permanently, and the different components will be swapped between each other below it. There's actually nothing special about the <nav> element. It behaves exactly like a <div>. <nav> Is just a semantic element that gives your HTML more meaning when people read it.

So, our web app now looks like the left image - but do you see a difference between the left and the right?

There's one slightly annoying thing about React here - React strips out whitespace between elements. If we write <Link> components next to each other, even if they're on new lines, React strips all of the whitespace (spaces, returns, tabs...) between them and squishes them all together.

We must insert a space manually by writing {' '} in order to get spaces between our links.

So instead, here's how we'll write the links. Nothing has changed except that we've added the space:

<Link to="/">Go to Home Page</Link>{' '}
<Link to="/procedures">See Our Procedures</Link>{' '}
<Link to="/contact">Contact Us!</Link>

And now the nav bar will have spaces like it should.

Final Code

Here's what our final App.js looks like:

class App extends Component {
  render() {
    return (
      <Router>
        <div>
          <nav>
            <Link to="/">Go to Home Page</Link>{' '}
            <Link to="/procedures">See Our Procedures</Link>{' '}
            <Link to="/contact">Contact Us!</Link>
          </nav>
          <Route exact path="/" component={Home} />
          <Route path="/procedures" component={Procedures} />
          <Route path="/contact" component={Contact} />
        </div>
      </Router>
    );
  }
}

export default App;

Check it out! Does yours work?