Send Firebase Auth Token To Nodejs Server

i want to let the client login with firebase through the front-end. later i want to send the token that verifies that he's logged in to my server, so that i can check if some info about him on the database. e.g: if he paid for a specific course.

the firebase documentation doesn't provide actual code on how to send it to my own server:

firebase.auth().currentUser.getIdToken(/* forceRefresh */ true).then(function(idToken) {
  // Send token to your backend via HTTPS
  // ...
}).catch(function(error) {
  // Handle error
});

so, i'm looking for an idea or preferably some code on how to send the token to the server with each request.

Lots of ways you can do it. I like using Axios https://github.com/axios/axios

axios.post('/your-endpoint', {
    token: your-token
  })
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  });