How can I serve robots.txt on an SPA using React with Firebase hosting?

Question

I have an SPA built using create-react-app and wish to have a robots.txt like this:

http://example.com/robots.txt

I see on this pa

Answer 1

Just add the following rules to the "rewrites" section in firebase.json

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

Answer 2

In my /public directory, I created a robots.txt.

In my /src directory, I did the following:

I created /src/index.js:

import React from 'react'
import ReactDOM from 'react-dom'
import {TopApp} from './TopApp'
import registerServiceWorker from './registerServiceWorker'

import {BrowserRouter} from 'react-router-dom'

ReactDOM.render(
  <BrowserRouter>
    <TopApp/>
  </BrowserRouter>,
  document.getElementById('react-render-root')
)

registerServiceWorker()

I created /src/TopApp.js:

import React from 'react'

import {
  Switch,
  Route
} from 'react-router-dom'

import {ComingSoon} from './ComingSoon'
import {App} from './App'

export class TopApp extends React.Component {
  render() {
    return (
      <div className="TopApp">
        <Switch>
          <Route path='/MyStuff' component={App}/>
          <Route exact path='/' component={ComingSoon}/>
        </Switch>
      </div>
    )
  }
}

Because path /robots.txt is not covered by the router paths provided, it took it from my public directory and robots file was published as desired.

The same could be done for sitemap.xml.