Calling a function located in typescript file A from another typescript file B

I have the following code that is not executing properly

platform.tsx

  import { windowHelper } from "./windowHelper";
import { officeHelper } from "./officeHelper";
import { googleHelper } from "./googleHelper";
export class platformHelper {
 
    static callFCT = (fnctname: any, fnctparams = null) => {
        const platform = window.localStorage ? window.localStorage.getItem('platform') : "office";
        var fn: any = null;
        var wndhelper:any = new windowHelper();
        var offhelper:any = new officeHelper();
        var gghelper:any = new googleHelper();
        switch (platform) {
            case "window":
                fn = wndhelper[fnctname];
                break;
            case "office":
               
                fn = offhelper[fnctname];
                console.log(fn); //return undefined
                console.log(fnctname);
                break;
            case "google":
                fn = gghelper[fnctname];
                break;
            default:
                break;
        }
        // is object a function?
        if (typeof fn === "function") fn.apply(null, fnctparams);
    }
}

OfficeHelper.tsx

    export class officeHelper {
  constructor() { }
static GetEmail = () => {
    return Office.context.mailbox.userProfile.emailAddress;
  }
}

login.tsx

 let userEmailAddress = platformHelper.callFCT("GetEmail"); 
 console.log(userEmailAddress ) // UNDEFINED

The fn function is always undefined and the email address is not being returned as GetEmail is not being called

>Solution :

In your code, GetEmail is a static function of officeHelper class, so you have to access it through officeHelper.GetEmail (or officeHelper["GetEmail"]), instead of new officeHelper().GetEmail.

Then, as pointed out in the question comments and other answers, do not forget to return the result of fn.apply.