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Normally when I wanted to catch an event on a page in js:

window.onkeydown = function (event) {
    //Do something here
I cannot seem to figure out (or Google) how to do this in typescript. For the setup I am working in, there is a ts file for the page, and a ts file for the class that it is loading. 
                If there is something that accomplishes the above, for typescript, then it is an alternative
– TopBanana9000
                Jul 29, 2016 at 13:54
                Can you explain a bit more about the environment? Are you compiling the code to run on a browser or interpreting somewhere?
– Ismael Miguel
                Jul 29, 2016 at 13:55
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
                There is no need for this if your project is setup correctly.  lib.d.ts defines window with an onkeydown property.
– AlexG
                Jul 29, 2016 at 14:06
                Get Type '(event: React.KeyboardEvent<Element>) => void' is not assignable to type 'EventListener'.
– Tunn
                Feb 13, 2020 at 0:18
                In case of using this with React make sure you don't accidentally use import { KeyboardEvent } from "react";. This leads to the not assignable to type 'EventListener' exception. Instead the KeyboardEvent from globalThis must be used (i.e. simply remove the import statement)
– luk
                Aug 14, 2020 at 9:57
windows.addEventListener('keydown', (event: KeyboardEvent) =>{
 // if you need event.code
windows.addEventListener('keydown', (event: Event) =>{
 // event
        
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