CodeSnips

sql

-- Publisher: Send notification
NOTIFY new_order, 'Order #12345 created';

-- Subscriber: Listen for notifications
LISTEN new_order;

PostgreSQL LISTEN/NOTIFY for pub-sub messaging

postgresql listen-notify pub-sub

by Maria Garcia 2 tabs

ruby

class CheckoutService
  def initialize(cart:, user:)
    @cart = cart
    @user = user
  end

Instrument a Service with Notifications

rails observability instrumentation

by codesnips 3 tabs

typescript

export type EventMap = Record<string, unknown[]>;

type Listener<Args extends unknown[]> = (...args: Args) => void;

export class TypedEmitter<Events extends EventMap> {
  private listeners = new Map<keyof Events, Set<Listener<any>>>();

Type-Safe Event Emitter With Strongly-Typed Listener Payloads in TypeScript

typescript events event-emitter

by codesnips 3 tabs

javascript

const { EventEmitter } = require('events');

class NotificationBus extends EventEmitter {
  constructor(bufferSize = 100) {
    super();
    this.setMaxListeners(0);

Server-Sent Events for Live Notifications with a Reconnectable EventSource Hook

sse server-sent-events eventsource

by codesnips 3 tabs