React router not working after building the app

Edit:

The best way to do it is using the public URL where it will be deployed as the basename prop in the Router component. It could also be something like PUBLIC_URL=myproject, and it would make the build assuming the app is served at https://<domain-name>/myproject/index.html.

<Router basename={process.env.PUBLIC_URL}>
...
</Router>

Old answer:

First of all, this is not an issue with React Router. Notice that in your package.json, you have:

  "homepage": "./",
  "private": true,

The short answer is, if you change the value of "homepage" and make it "", or the URL of the homepage of the site where it is actually deployed, it will work directly.

"homepage": "",

OR

"homepage": "mysite.com/",

Here's why I think that works, in detail:

If you now use react-scripts build, it creates a file - build/index.html which imports JS files like <script src="./static/js/main.9ea6b007.chunk.js">.

Now, when you're using react-router, you ideally want to route all requests to build/index.html. So you may build a proxy server to serve your index.html and static files as follows (using Express.js):

const express = require('express');
const path = require('path');
const bodyParser = require('body-parser');

const app = express();
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

app.use(express.static(path.join(__dirname, 'build')));

app.use('/', (req, res) => {
  res.sendFile(path.join(__dirname, 'build/index.html'));
});

app.listen(process.env.PORT || 3000, () => console.log(`Running on PORT ${process.env.PORT || 3000}`));

Now you see that all your requests - except the ones for static files - return the index.html file. So, all your JS and CSS files will be returned when you request /static/js/main.9ea6b007.chunk.js. Notice how that's different from what is in your index.html source? The src in the index.html tries to request from ./static/..., and the . is interpreted as the current route.

So let's say you were to visit localhost:3000/abcd expecting your desired page to show up. Let's examine what happens here.

• You get the index.html as you expected.
• The index.html tries to request ./static/..., which translates to localhost:3000/abcd/static/..., whereas you wanted it to be localhost:3000/static/.... And anything that is not /static is going to return the same index.html, so even the JS files return the same page resulting in a console error Uncaught SyntaxError: Unexpected token '<'.
• If you go to your browser Devtools and check out the sources, all your JS and CSS files would have the same content as index.html.

Therefore, the homepage in your package.json is used in the index.html as a prefix to all static files, in the form <homepage>/static/.... Hence it needs to be "" so that the requests are to /static/... or "mysite.com/", so that the requests are to mysite.com/static/....

I initially had the similar issue when I deployed my React app on Firebase Hosting.

It turned out that the issue was actually not with the react-router, as suggested by the poster of the accepted answer. HashRouter would append the /#/ in front of our URL, which doesn't look really pretty, no matter what.

I found out that the issue was with the web hosting service we use. We would need to indicate the default HTML file that we want to render, which is the index.html.

This happens because our hosting service provider (be it Amazon's S3 / Apache / Google Cloud Platform (GCP)'s App Engine / Firebase Hosting, etc) doesn't know which HTML file to render if a URL other than the default URL (https://www.link_to_your_website.com) was given. For instance, it won't be able to recognise https://www.link_to_your_website.com/login.

In Firebase Hosting, you would need to do:

"rewrites": [ {
    "source": "**",
    "destination": "/index.html"
}]

In Apache's .htaccess, you would need to do:

FallbackResource /index.html

Source: How to redirect an error 404 to home page with .htaccess?

These commands will tell them to render index.html no matter what because React-Route is going to dynamically update the HTML DOM's tree with the new React Elements.

Hope that those who faced this similar issue find this helpful.

This is a potential server related issue. You probably got Apache running and it is listening on :80.

For Apache server:

Make sure your Apache server redirects every request to index.html file. Make sure the following code is present in .htaccess

Options -MultiViews
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.html [QSA,L]

After getting stuck on react-router for a couple of days, I read the documentation in React Training. Then I followed the quick start steps and modified it to satisfy my requirements.

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

  <Router>
    <div>
      <Header />
      <Route exact path="/" component={Content} />
      <Route path="/:country" component={SnaContent} />
      <Footer />
    </div>
  </Router>

This have fixed the issue for now. Hope its helpful for others who faced similar issue.