Check Production and Staging environment inside HTML file in a React App

I am trying to integrate a 3rd party app inside my React App. I have to use different keys for production and staging but I am unable to figure out how to achieve that in React and Node applications I can do it by process.env but in index.html I am unable to figure out how can I achieve that.

Here is my pseudocode which I am trying to pull for my index.html file for my React project

<script>
if(env === production){
  some_app.init('TOKEN_FOR_PRODUCTION');
}
else{
  some_app.init('TOKEN_FOR_STAGING_OR_DEV');
}
</script>