injection example.js

/// browser code we test against, using axios
function onClick () {
  const ajaxRequestPromise = axios.get('/service-call'); // make the service call
  ajaxRequestPromise.then(response => { // do something with the response
    doSomethingFruity(response.data);
  });
}
                                
myButton.onclick = onClick; // bind to button

/////////////////////

// if we wanted to know if the service call is made, we could inject this
const _axiosGet = axios.get; // preserve the original function
axios.get = function (url) { // monkey patch
  magicallyReportCallToService(); // somehow let selenium know the call was made?
  return _axiosGet.apply(null, arguments); // pass the arguments to the original function. The caller (onClick) is none the wiser :)
}