Dispatch Keyboard events to simulate keypress

[prenx4x]

Hello,
I am trying to add a row of buttons on top of on-screen keyboard.

The app is a smart calculator app where users can type expressions to get answers.
I added a dispatch event like

document.addEventListener("keydown", (e) => {
  console.log(e);
});

function pressKey(key: string) {
  document.dispatchEvent(
      new KeyboardEvent("keydown", {
        key,
      })
    );

I can actually see the event being fired but isTrusted is false for obvious reason. Thus how do I allows this functionality in proper way? is there official way to have such a button and allow trusted keypresses?

Thanks.