Code Explainers

Code explainers tagged #observer-pattern

typescript 
type ToastVariant = "info" | "success" | "warning" | "error";
 
interface Toast {
  id: string;

A self-dismissing toast store with dedup

observer-pattern deduplication timers
Intermediate 10 steps
python 
import json
import logging
import threading
from pathlib import Path

A hot-reloading config file watcher

file-watching thread-safety hot-reload
Intermediate 7 steps
typescript 
type EventMap = Record<string, unknown>;
 
type Handler<T> = (payload: T) => void;
 

A type-safe event bus in TypeScript

generics event-emitter type-safety
Advanced 7 steps
php 
<?php
 
namespace App\Events;
 

A priority event dispatcher in PHP

observer-pattern callbacks priority-ordering
Intermediate 8 steps
typescript 
type EventMap = Record<string, unknown[]>;
 
type Listener<Args extends unknown[]> = (...args: Args) => void;
 

A type-safe event emitter in TypeScript

generics mapped-types event-emitter
Advanced 8 steps
ruby 
class EventEmitter
  def initialize
    @listeners = Hash.new { |hash, key| hash[key] = [] }
  end

Building an EventEmitter in Ruby

pub-sub closures callbacks
Intermediate 7 steps