Files
notebrook-notes/frontend/src/events/messaging-system.ts
2024-09-03 14:50:33 +02:00

61 lines
2.0 KiB
TypeScript

export type Message<T> = {
type: string,
data?: T,
};
export type MessageHandler<T> = (message: Message<T>) => void;
export class MessagingSystem {
private handlers: Record<string, MessageHandler<any>[]> = {};
public registerHandler<T>(type: string, handler: MessageHandler<T>): void {
if (!this.handlers[type]) {
this.handlers[type] = [];
}
if (!this.handlers[type].includes(handler)) {
this.handlers[type].push(handler);
}
}
public unregisterHandler<T>(type: string, handler: MessageHandler<T>): void {
if (this.handlers[type]) {
this.handlers[type] = this.handlers[type].filter(h => h !== handler);
}
}
public registerHandlerOnce<T>(type: string, handler: MessageHandler<T>): void {
const wrappedHandler = (message: Message<T>) => {
handler(message);
this.unregisterHandler(type, wrappedHandler);
};
this.registerHandler(type, wrappedHandler);
}
public waitForMessage<T>(type: string, timeout?: number): Promise<T> {
return new Promise((resolve, reject) => {
const handler = (message: Message<T>) => {
if (timer) clearTimeout(timer);
resolve(message.data!);
this.unregisterHandler(type, handler);
};
this.registerHandler(type, handler);
let timer: ReturnType<typeof setTimeout> | undefined;
if (timeout) {
timer = setTimeout(() => {
this.unregisterHandler(type, handler);
reject(new Error(`Timeout waiting for message of type '${type}'`));
}, timeout);
}
});
}
public sendMessage<T>(message: Message<T>): void {
const handlers = this.handlers[message.type];
if (handlers) {
handlers.forEach(handler => handler(message));
}
}
}