streamdeck-typescript/src/manager/event.manager.ts

This library will help you build elgato stream deck plugins in typescript

/*
 * Author: XeroxDev <help@xeroxdev.de>
 * Copyright (c) 2021.
 *
 */

import { IllegalArgumentError } from '../errors/illegal-argument.error';
import { PossibleEventsToReceive } from '../interfaces/types';

/**
 * Singleton class for EventManager
 * @internal
 */
export class EventManager {
    private static _INSTANCE: EventManager;
    private registeredEvents: Map<string, Function[]> = new Map<
        string,
        Function[]
    >();

    private constructor() {}

    /**
     * Returns EventManager instance
     * @returns {EventManager}
     * @internal
     * @constructor
     */
    public static get INSTANCE(): EventManager {
        if (!this._INSTANCE) this._INSTANCE = new EventManager();
        return this._INSTANCE;
    }

    /**
     * Helper for decorators
     * @internal
     * @param {string} event
     * @param target
     * @param {string | symbol} propertyKey
     * @param {TypedPropertyDescriptor<any>} descriptor
     * @returns {TypedPropertyDescriptor<any>}
     * @constructor
     */
    public static DefaultDecoratorEventListener(
        event: string,
        target: any,
        propertyKey: string | symbol,
        descriptor: TypedPropertyDescriptor<any>
    ) {
        const eventListener = <T>(actionName: string, instance: T) => {
            if (typeof actionName !== 'string') {
                throw new IllegalArgumentError(
                    `actionName needs to be of type string but ${typeof actionName} given.`
                );
            }
            EventManager.INSTANCE.registerEvent(
                event,
                <T>(eventActionName: string | false, ...params: any[]) => {
                    if (
                        !eventActionName ||
                        actionName === '*' ||
                        eventActionName === '*' ||
                        actionName === eventActionName
                    )
                        descriptor.value.apply(instance, params);
                }
            );
        };

        if (!target._sd_events) {
            target._sd_events = [];
        }

        target._sd_events.push(eventListener);

        return descriptor;
    }

    /**
     * Registers event
     * @internal
     * @param {string} eventName
     * @param {Function} callback
     */
    public registerEvent(eventName: string, callback: Function) {
        if (!this.registeredEvents.has(eventName))
            this.registeredEvents.set(eventName, []);
        this.registeredEvents.get(eventName)?.push(callback);
    }

    /**
     * Calls event
     * @internal
     * @param {PossibleEventsToReceive} eventName
     * @param {string} actionName
     * @param params
     */
    public callEvents(
        eventName: PossibleEventsToReceive,
        actionName: string = '*',
        ...params: any[]
    ) {
        this.registeredEvents
            .get(eventName)
            ?.forEach((val) => val(actionName, ...params));
    }
}