tridactyl/src/keydown_background.ts

// Interface: onKeydown.addListener(func)
//
import * as Messaging from "./messaging"

import { MsgSafeKeyboardEvent } from "./msgsafe"

type KeydownCallback = (keyevent: MsgSafeKeyboardEvent) => void

const listeners = new Set<KeydownCallback>()
function addListener(cb: KeydownCallback) {
    listeners.add(cb)
    return () => {
        listeners.delete(cb)
    }
}

export const onKeydown = { addListener }

// Receive events from content and pass to listeners
export function recvEvent(event: MsgSafeKeyboardEvent) {
    for (let listener of listeners) {
        listener(event)
    }
}

// Get messages from content
import * as SELF from "./keydown_background"
Messaging.addListener("keydown_background", Messaging.attributeCaller(SELF))