You can achieve this with: EventTarget.dispatchEvent(event)
and by passing in a new KeyboardEvent as the event.
For example: element.dispatchEvent(new KeyboardEvent('keypress', {'key': 'a'}))
Working example:
// get the element in question_x000D_
const input = document.getElementsByTagName("input")[0];_x000D_
_x000D_
// focus on the input element_x000D_
input.focus();_x000D_
_x000D_
// add event listeners to the input element_x000D_
input.addEventListener('keypress', (event) => {_x000D_
console.log("You have pressed key: ", event.key);_x000D_
});_x000D_
_x000D_
input.addEventListener('keydown', (event) => {_x000D_
console.log(`key: ${event.key} has been pressed down`);_x000D_
});_x000D_
_x000D_
input.addEventListener('keyup', (event) => {_x000D_
console.log(`key: ${event.key} has been released`);_x000D_
});_x000D_
_x000D_
// dispatch keyboard events_x000D_
input.dispatchEvent(new KeyboardEvent('keypress', {'key':'h'}));_x000D_
input.dispatchEvent(new KeyboardEvent('keydown', {'key':'e'}));_x000D_
input.dispatchEvent(new KeyboardEvent('keyup', {'key':'y'}));
_x000D_
<input type="text" placeholder="foo" />
_x000D_