ClassFunctionKeyMapper.ts

class MyClass {
  public myProp = 13;
  public static readonly myStaticReadOnlyProp = 99;
  private myPrivateProp: string | undefined;

  constructor() {
    this.myPrivateProp = undefined;
  }

  public myPublicFunction() {
    return 1;
  }

  public myPublicFunction2(arg: string): Promise<void> {
    return Promise.resolve();
  }

  private myPrivateFunction() {return false;}

}

const keyOf: keyof MyClass = 'myPublicFunction2'
type MyFunctions<T> = {
  [K in keyof T & string]: T[K] extends Function ? `func-${K}` : never
}[keyof T & string]

const funcName: MyFunctions<MyClass> = 'func-myPublicFunction2';
const instance = new MyClass()
function stubFunction<T extends MyClass>(instance: T, method: MyFunctions<T>){
  console.log(`class: ${instance} - ${method} : result ${instance[method]()}`);
}