Check your version
This post assumes you're using React Router v5. If not, find your version below.

Here's the scenario. It's April 2020. Covid-19 is nbd yet and there's an excess of venture capital and you've managed to snag some by pitching your "Twitter for minimalists" app. You're a long time contributor to Hacker News so you're confident you can knock it out in a weekend.

The app is simple with only three routes - /, /notifications, and /:handle.

You're a few hours in and you hit a snag. You run rm -rf node_modules && npm install, no luck. You check Twitter. You come back to your app. It's still broken.

You take a look at your Routes.

<Route exact path='/'><Home /></Route>
<Route path='/notifications'><Notifications /></Route>
<Route path='/:handle'><Profile /></Route>

The issue you're running into is that every time you navigate to /notifications, not only does the Notifications component render, but so does the Profile component since /:handle is also matching. What you need is a way to tell React Router to not match on /:handle if /notifications already matched. You decide to google "ambiguous matches" and you find this post, meta.

First, let's create our navbar to navigate between our three routes. We'll use /tylermcginnis and /dan-abramov to represent our dynamic user links.

import React from "react";
import { BrowserRouter as Router, Link } from "react-router-dom";
export default function App() {
return (
<Router>
<div>
<ul>
<li>
<Link to="/">Home</Link>
</li>
<li>
<Link to="/notifications">Notifications</Link>
</li>
<li>
<Link to="/tylermcginnis">Tyler (dynamic)</Link>
</li>
<li>
<Link to="/dan_abramov">Dan (dynamic)</Link>
</li>
</ul>
</div>
</Router>
);
}

Now that we have our navbar setup, let's create our components that we'll be rendering. We'll have Home, Notifications, and Profile.

const Home = () => <h2>Home</h2>;
const Notifications = () => <h2>Notifications</h2>;
const Profile = () => {
const { handle } = useParams();
return (
<div>
<h2>Profile: {handle}</h2>
</div>
);
};

Now comes the point of this post. Earlier we mentioned that our Routes looked like this -

<Route exact path='/'><Home /></Route>
<Route path='/notifications'><Notifications /></Route>
<Route path='/:handle'><Profile /></Route>

The problem, as mentioned earlier, is every time you navigate to /notifications, not only does the Notifications component render, but so does the Profile component since /:handle is also matching. What we need is a way to tell React Router v5 to not match on /:handle if /notifications already matched. Another way to put that is we only want to render the first Route that matches, not every Route that matches which is the default behavior.

To do this, you can wrap your Routes inside of the Switch component that comes with React Router v5.

<Switch>
<Route exact path="/" component={Home} />
<Route path="/notifications" component={Notifications} />
<Route path="/:handle" component={Profile} />
</Switch>

Before you leave

I know, another newsletter pitch - but hear me out. Most JavaScript newsletters are terrible. When’s the last time you actually looked forward to getting one? Even worse, when’s the last time you actually read one? We wanted to change that.

We call it Bytes, but others call it their favorite newsletter.

Delivered to 109,984 developers every Monday and Thursday