codesnips
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
python 
from typing import List, Optional

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from .dataloader import DataLoader

Batched DataLoader to Avoid N+1 Queries in FastAPI Responses

fastapi dataloader n-plus-one
by codesnips 3 tabs
php 
<?php

namespace App\Domain;

use InvalidArgumentException;

Serializing a Money Value Object with a Custom Symfony Normalizer

symfony serializer value-object
by codesnips 3 tabs
javascript 
import { useCallback, useEffect, useRef } from 'react';

export function useRafThrottle(callback) {
  const savedCallback = useRef(callback);
  const frame = useRef(null);
  const latestArgs = useRef([]);

Throttling a Scroll-Driven Reading Progress Bar with requestAnimationFrame in React

react hooks scroll
by codesnips 4 tabs
java 
package com.example.ratelimit;

public class TokenBucket {

    private final long capacity;
    private final long refillTokens;

Per-Client Token Bucket Rate Limiting with a Spring Boot HandlerInterceptor

spring-boot rate-limiting token-bucket
by codesnips 4 tabs
python 
import time
import threading
from collections import deque, defaultdict


class SlidingWindowLimiter:

Sliding-Window Rate Limiting in Flask With a Custom Decorator and In-Memory Buckets

flask rate-limiting decorators
by codesnips 3 tabs
python 
from marshmallow import (
    Schema, fields, validates, validates_schema,
    ValidationError, RAISE,
)
from marshmallow.validate import Length, Email, Equal

Field-Level Signup Validation in Flask with Marshmallow Schemas

flask marshmallow validation
by codesnips 3 tabs
ruby 
class RevenueStat
  DEFAULT_RANGE = 30.days

  def initialize(account, range: DEFAULT_RANGE)
    @account = account
    @range = range

Memoized Query Object for a Cached Dashboard Stat in Rails

rails activerecord query-object
by codesnips 3 tabs
ruby 
class OnboardingForm
  include ActiveModel::Model
  include ActiveModel::Attributes

  STEPS = %i[account profile preferences].freeze

Multi-Step Wizard Form in Rails with a Form Object and Session-Backed State

rails form-objects activemodel
by codesnips 3 tabs
java 
package com.example.security;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

Method-Level Role Authorization with a Custom @RequireRole Annotation and Spring AOP

spring spring-boot aop
by codesnips 4 tabs
java 
package com.shop.inventory;

import jakarta.persistence.*;

@Entity
@Table(name = "inventory_item")

Optimistic Locking on Inventory Updates with @Version and a Retrying Conflict Handler in Spring Boot

spring-boot jpa hibernate
by codesnips 3 tabs
go 
package optimistic

import (
	"errors"
	"sync"
)

Optimistic UI Rollback in Go With a Compensating Action Log

go concurrency optimistic-ui
by codesnips 3 tabs