JavaScript dispatch keydown event programmatically

dispatch-keydown-event.js

const KEY_CODE = {
  ARROW_DOWN: 40,
  BACKSPACE: 8,
  ENTER: 13,
};

/**
 * Dispatch keydown event.
 *
 * @param {number} keyCode
 * @returns {void}
 */
function keydown(keyCode) {
  const keyboardEvent = new KeyboardEvent('keydown', {
    bubbles: true,
    cancelable: true,
    keyCode,
  });
  document.body.dispatchEvent(keyboardEvent);
}