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5 Remarkable React Router Features (Anchor Links, Query Params & more)

Gedalya Krycer
Front-End Developer and Designer with a focus on React.
・6 min read

Overview

I love React Router and how it truly expands the use case for React. Today we will take a quick look at what it does and then dive into 5 features and tricks that I feel are pretty remarkable.

Route to a section:

Refresher

What is it?

React Router is a game-changing package that allows us to turn our React SPA (single page application), into a virtual "multi-page" experience.

Why do we need it?

Typically when we navigate to a new page, the client (browser) sends a request to the server and indicates that a particular route (page) needs to be accessed. (For example, the /about route would deliver the about.html file.)

However, React is anything but typical and operates only on the client-side. Therefore we can't request a new page from the server, because we only have access to the index.html file. So we need a way to at least mimic multiple pages in our SPAs.

What does it do?

React Router intercepts this request on the client-side and instead renders a new component that we specify.

For example, it would render a component called <AboutPage /> which in turn holds <Bio /> and <Skills /> children components that make up the content of that "page".

It looks like we went to a new "About" page, with a new URL slug* and content. In reality, we are still in our trusty index.html file with its content being rapidly replaced based on routing. 🀯

*The slug follows the main domain and explains what the page is: website.com/this-is-the-slug

Completly new to React Router? Check out the resource links at the bottom to get started on the basics first.

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Remarkable Features & Tricks

1️⃣ Fixing Anchor Links

Ok, this is more of a trick than a feature, but you would think creating an anchor link should be simpler than it is.

A logical assumption would be that <Link to='/about#skills'> would take us to the <About /> component and auto-scroll to the "skills" section.

Sadly this doesn't work out of the box, but there is a simple add-on package that comes to the rescue.

  1. $ npm install --save react-router-hash-link

  2. Import the package into your component.

  3. <Link> now accepts a hash anchor URL πŸŽ‰

...
import { HashLink as Link } from 'react-router-hash-link';

<Link to='/about#skills'>Skills</Link>
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2️⃣ Building Relative Paths

There comes a time when we need to nest routes within other components. For example, linking to a blog post within a certain category.

Our target URL should look like: website.com/pets/catsvsdogs

The problem is that React Router will direct you to the main domain website.com/catsvsdogs and not append the post slug to the /pets/ category as shown above.

This is because by default it treats anything you are linking to as an Absolute path. What we really need is a path relative to the page you are on.

Hard-Code Solution πŸ‘Ž

Hard-coding a relative path is not recommended because if you ever change the parent(s) route further up the URL slug, the path would break.

// Hard-coding the category and post slugs
<Link to='/pets/catsvsdogs'>Cats vs Dogs</Link>
<Route path='/pets' component={blogPost}/>

// The above will break if we make this change to the route
<Route path='/animals' component={blogPost}/>
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Dynamic Solution (Hooks) πŸ‘

A much better solution is to leverage the url property from the match object that each <Route /> has. This allows us to dynamically place the current route's URL within the <Link />. and <Route />.

The useRouteMatch() hook lets us destructure the url and the path properties from the match object.

The path property is similar to the url, but is used with <Routes />.

To make everything truly dynamic, let's also convert the above code into a map that generates a postId as part of the <Link> URL parameters. Then we will set up the <Route /> to accept any id, by adding /:postId at the end of its path.

import { Route, Link, useRouteMatch } from 'react-router-dom';

// Custom Hook
const {path, url} = useRouteMatch();

// Dynamic list of blog post links.
<ul>
  {postsArray.map(({id, name}) => (
   <li key={id}>
     <Link to={`${url}/${id}`}>{name}</Link>
   </li>
  ))}
</ul>

// Route uses the path property to tell which URL it should match and accepts a dynamic id
<Route path={`${path}/:postId`} component={blogPost}/>
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Dynamic Solution (Classes) πŸ‘

With class-based components, we can essentially take the same process as above. Instead of using a hook, we access the url in the match object via props.

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

// Dynamic list of blog post links.
<ul>
  {postsArray.map(({id, name}) => (
   <li key={id}>
     <Link to={`${this.props.match.url}/${id}`}>{name}</Link>
   </li>
  ))}
</ul>

// Route uses props to get the matching url and accepts a dynamic id
<Route path={`${this.props.match.url}/:postId`} component={blogPost}/>
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3️⃣ Passing Props via withRouter()

Routes come with a robust set of information that is delivered in the form of props. For example, we can extract params we had set up or a different location to navigate to. (Prop data is stored in location, match, and history objects.)

Often times in our projects we have a component that is not associated with a route but could benefit from the above props. We could pop-drill the data we want, but that could get confusing and messy quickly.

Instead, we can use the higher-order component withRouter() on the component that just needs quick access to the props. For example, a form that wants to history.push() to a location such as a confirmation screen.

β€’β€’β€’
import { withRouter } from 'react-router';

const Form = () => {

  // This function uses the route props to go to a new page after handling the form submission
  const handleSubmit = (event) => {
    β€’β€’β€’
    props.history.push(`/confirmation`)
  };

  <form onSubmit={handleSubmit}>
    β€’β€’β€’
  </form>

}

// Higher-order component that exposes the closest route's props to the Form component
export default withRouter(Form) 
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4️⃣ Passing Data via URL Query Params

React Router lets us pass data through the URL so that it can be consumed by the linked-to component. Appending this data to the URL is called query parameters.

useLocation() & custom extraction hook

import {
  β€’β€’β€’
  Link,
  useLocation
} from 'react-router-dom';

// React Router suggests this custom hook to pull the value from the url
const useQuery = () => {
  return new URLSearchParams(useLocation().search);
}

// Component that has the data we want to send
const ParentComponent = () => {

  // Hook from above
  let query = useQuery();

  return (
    <div>
      {/* Data is added after the "?" */}
      <Link to='/account?name=netflix'>Netflix</Link>

      {/* Data is pulled out of the URL and passed as a prop to the child component  */}
      <ChildComponent name={query.get('name')} />
    </div>
  );
}

// Component receiving query params props 
const ChildComponent = ({name}) => {
  return <h1>{name}</h1>
}
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useParams() Hook

import { useParams } from 'react-router-dom';

const Blog = () => {
  return (
    {/* Link passes in an id as params in the slug*/}
    <Link to={`${props.match.url}/${id}`} />Post Name</Link>

    {/* Route is set up to dynamically accept any id passed in the slug */}
    <Route path=`${props.match.url}/:id`>
      <BlogPost />
    </Route>
  )
}

const BlogPost = () => {

  {/* useParams pulls the id param out of the slug so it can be used */}
  let { id } = useParams();
  return <div>Now showing post {id}</div>;

}
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5️⃣ Styling Active Links

A simple upgrade to a site's UX is to show an active style in the navigation for whatever page is showing.

Alt Text

React Router makes this simple with the <NavLink /> component, which replaces the standard <Link />.

import { NavLink } from 'react-router-dom';

<NavLink to='/' exact>Home</NavLink>
<NavLink to='/about'>About</NavLink>
<NavLink to='/contact'>Contact</NavLink>

// Note that the "Home" link has the prop "exact". 
// This prevents it from activating unless it's clicked.
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This new component adds an .active CSS class to any link that has its page shown. We can then target that generated class with any style we prefer.

.nav__link:hover, 
.nav__link:active,
.nav__link.active { <--- React Router Generated
  color: green;
}
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If we don't want to use the class name .active we can even specify our own name. This just needs to be passed to the activeClassName prop.

import { NavLink } from 'react-router-dom';

<NavLink 
  to='/' 
  exact 
  activeClassName='nav__link--active' <-------
>Home</NavLink>
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Alternatively, we could use the activeStyle JS styles prop to update the component directly.

import { NavLink } from 'react-router-dom';

<NavLink 
  to='/' 
  exact 
  activeStyle={{
    color: 'green'
  }}
>Home</NavLink>

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Summary

Alright, my friends, that is it for today. I hope you learned something new about React Router that will help your next project.

If you are looking to dig deeper, check out the various resources below. Happy coding! πŸ€“


Resource Links


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