Advanced code explainers

php

<?php
 
namespace App\Jobs;

Debouncing a Laravel shipping-rate job

queues debouncing atomic-locks

Advanced 9 steps

typescript

import { useState, useEffect, useRef, useCallback } from "react";
 
interface Suggestion {
  id: string;

A debounced autocomplete hook in React

debounce custom-hooks abortcontroller

Advanced 7 steps

ruby

class Product < ApplicationRecord
  scope :search, ->(query) {
    return all if query.blank?

Building a multi-term search scope in Rails

arel scopes full-text search

Advanced 7 steps

typescript

type Middleware<TIn, TOut> = (ctx: TIn) => Promise<TOut> | TOut;
 
class Pipeline<TIn, TOut> {
  private constructor(private readonly run: Middleware<TIn, TOut>) {}

A type-safe async middleware pipeline

generics type-safety middleware

Advanced 9 steps

ruby

class Spellchecker
  ALPHABET = ('a'..'z').to_a.freeze
 
  def initialize(dictionary)

Building a Norvig-style spellchecker in Ruby

edit-distance levenshtein dynamic-programming

Advanced 10 steps

javascript

import { NextResponse } from 'next/server';
import { db } from '@/lib/db';
 
function csvCell(value) {

Streaming a CSV export in a Next.js route

streaming csv readablestream

Advanced 9 steps

go

package logging
 
import (
	"fmt"

Redacting secrets with Go reflection

reflection recursion struct-tags

Advanced 10 steps

ruby

class Document < ApplicationRecord
  class StaleObjectError < StandardError
    def initialize(id)
      super("Document ##{id} was modified by another process")

Optimistic locking with retries in Rails

optimistic-locking concurrency transactions

Advanced 8 steps

rust

use axum::{
    body::{Body, Bytes},
    extract::Request,
    http::StatusCode,

Logging request and response sizes in Axum

middleware http streaming-bodies

Advanced 8 steps

go

func (h *ExportHandler) StreamExport(c *gin.Context) {
	datasetID := c.Param("id")
 
	ctx := c.Request.Context()

Streaming NDJSON progress with Gin

streaming goroutines channels

Advanced 8 steps

go

package handler
 
type flightResult struct {
	status int

Deduping in-flight requests in Gin

middleware concurrency deduplication

Advanced 9 steps

rust

use std::sync::Arc;
use axum::{
    extract::{Multipart, State},
    http::StatusCode,

Throttling file uploads in Axum with a Semaphore

concurrency backpressure multipart

Advanced 8 steps

php

<?php
 
namespace App\Queue;

Deduplicating a job queue with Redis

deduplication redis atomicity

Advanced 8 steps

javascript

import { NextResponse } from 'next/server';
import { Redis } from '@upstash/redis';
 
const redis = Redis.fromEnv();

Sliding-window rate limiting in a Next.js route

rate-limiting redis sorted-set

Advanced 8 steps

ruby

class WebhookSignatureConstraint
  def initialize(provider)
    @provider = provider
  end

Verifying webhook signatures with Rails routing constraints

routing constraints hmac webhooks

Advanced 7 steps

ruby

module UniqueJob
  extend ActiveSupport::Concern
 
  class_methods do

Deduplicating Active Job enqueues in Rails

concurrency idempotency caching

Advanced 9 steps

rust

use axum::{
    extract::{FromRequestParts, Host},
    http::{request::Parts, StatusCode},
};

Multi-tenant DB routing in Axum extractors

multi-tenancy extractors connection-pooling

Advanced 8 steps

go

func UserDashboardCache(rdb *redis.Client, ttl time.Duration) gin.HandlerFunc {
	return func(c *gin.Context) {
		claims, ok := c.Get("claims")
		if !ok {

Per-user response caching in Gin with Redis

middleware caching redis

Advanced 9 steps