Adding window.event handler to typescript

To answer more clearly:

const controlDown = (event: KeyboardEvent) => {
    console.log(event);
};
window.addEventListener('keydown', controlDown);

windows.addEventListener('keydown', (event: KeyboardEvent) =>{
 // if you need event.code
});

windows.addEventListener('keydown', (event: Event) =>{
 // event
});

This

window.addEventListener('keydown', keyDownListener, false)

window is defined will all events in lib.d.ts and this particular listener as

 addEventListener(type: "keydown", listener: (ev: KeyboardEvent) => any, useCapture?: boolean): void;

or this, if you want to keep your original "style",

window.onkeydown = (ev: KeyboardEvent): any => {
     //do something
}