How to show a loading bar when changing routes in NextJS

#nextjs #loading #nprogress #route

Setting up

I spent days trying to find the right thing to google on how to setup the blue loading bar that shows at the top of your screen when navigating between routes in NextJS. It's important to have this loading indicator to signify that a route change is occuring to avoid users assuming that the application has frozen.
This article assumes that you already have NextJS setup. To get started, we need to install the nprogress library.
Run

npm install nprogress

In _app.js

Inside pages/_app.js, add the following piece of code.

import NProgress from "nprogress"
import Head from "next/head"
import Router from "next/router"

Router.onRouteChangeStart = url => {
  NProgress.start()
}

Router.onRouteChangeComplete = () => NProgress.done()

Router.onRouteChangeError = () => NProgress.done()

export default function MyApp() {
    return (
        <>
            <Head>
               <link
                rel="stylesheet"
                href="https://cdnjs.cloudflare.com/ajax/libs    /nprogress/0.2.0/nprogress.min.css"
          />
             </Head>
              <Component {…pageProps} key={route} />
        </>
      )
}

Above, we access the Router object available inside next/router to ensure. onRouteChangeStart i.e when a Route change is in progress, NProgress will run i.e NProgress.start. Once the route change is done i.e onRouteChangeComplete, we call the done method on NProgress. We call the same method if there's an error.
I had issues using the NProgress stylesheet from the nprogress package within my application and resorted to using the stylesheet they provide via their CDN. Without the stylesheet, you won't notice anything on the screen.
Now, when you navigate to any page within your application, you should see a blue loading bar at the top of your screen

Top comments (10)

Comment deleted

Gyen Abubakar • Jul 7 '21

Can you explain why we should use this instead?

Ítalo Andrade • Jul 8 '21

You shouldn't. It actually doesn't really matter. I deleted the comment to avoid confusion.

Frulow • May 7 '23

`import NProgress from "nprogress";
import Router from "next/router";

Router.events.on("routeChangeComplete", () => NProgress.done());
Router.events.on("routeChangeStart", () => NProgress.start());
Router.events.on("routeChangeError", () => () => NProgress.done());`