Example of using a TypeScript generic type in a function's parameter and return type

async-task-handler-generic.ts

// MyType is a generic that we can pass different types when calling handleAsyncTask()
const handleAsyncTask = async function<MyType> (asyncFn: () => Promise<MyType | string>) : Promise<[boolean, MyType | undefined]> {
  const result = await asyncFn();
  if (typeof result === 'string') {
    return [true, undefined];
  }
  return [false, result];
}