ngInject - define injections as a static method in your class

ngInject.js

// ngInject.js
function ngInject(func) {
  if (func.ngInject)) {
    func.$inject = func.ngInject()
  }

  return func
}


// Auth/LoginController.js
class LoginController {
  static ngInject() {
    return ['userSession']
  }
  constructor(userSession) {
    this._userSession = userSession
  }
}


// Auth/index.js (the angular module definition)
angular.module('app.auth')
.controller('LoginController', ngInject(LoginController))