Defining TypeScript callback type

Question

I\'ve got the following class in TypeScript:

class CallbackTest
{
    public myCallback;

    public doWork(): void
    {
        //doing some work...
               


        

Answer 1

I'm a little late, but, since some time ago in TypeScript you can define the type of callback with

type MyCallback = (KeyboardEvent) => void;

Example of use:

this.addEvent(document, "keydown", (e) => {
    if (e.keyCode === 1) {
      e.preventDefault();
    }
});

addEvent(element, eventName, callback: MyCallback) {
    element.addEventListener(eventName, callback, false);
}