Intermediate code explainers

ruby

class ToastBroadcaster
  include ActionView::RecordIdentifier
 
  def self.broadcast_to(user, message:, type: :notice)

How Turbo Stream toasts broadcast in Rails

turbo-streams service-object real-time

Intermediate 6 steps

typescript

import { NestFactory } from '@nestjs/core';
import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
import { ValidationPipe } from '@nestjs/common';
import { ApiProperty } from '@nestjs/swagger';

Wiring validation and Swagger docs in NestJS

validation openapi decorators

Intermediate 8 steps

python

from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException, status
from pydantic import BaseModel, EmailStr
from sqlalchemy.orm import Session

Building a signup endpoint in FastAPI

dependency-injection request-validation background-tasks

Intermediate 8 steps

javascript

const ROLE_PERMISSIONS = {
  admin: ['users:read', 'users:write', 'billing:read', 'billing:write'],
  manager: ['users:read', 'billing:read'],
  member: ['users:read'],

Role-based permissions middleware in Express

authorization middleware rbac

Intermediate 9 steps

java

public interface GitHubClient {
 
    @GetExchange("/users/{username}")
    GitHubUser getUser(@PathVariable String username);

Declarative HTTP clients in Spring

http-client declarative-api proxy

Intermediate 8 steps

php

<?php
 
namespace App\Console\Commands;

Releasing stale document locks in Laravel

artisan-command transactions row-locking

Intermediate 6 steps

ruby

class TemplateInterpolator
  PLACEHOLDER = /\{\{\s*([\w.]+)\s*\}\}/
 
  def initialize(strict: false)

Interpolating templates with dotted keys in Ruby

regex string-interpolation hash-traversal

Intermediate 6 steps

typescript

import { Component, Input } from '@angular/core';
 
interface Order {
  id: string;

How Angular ICU plurals localize an order summary

i18n pluralization standalone-component

Intermediate 8 steps

python

from django import forms
from django.utils import timezone
 
from .models import Reservation

Multi-field validation in a Django ModelForm

form validation cross-field validation modelform

Intermediate 7 steps

java

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

Building a trie for autocomplete in Java

trie prefix-tree recursion

Intermediate 8 steps

go

package handlers
 
import (
	"net/http"

Serving embedded static meta files in Gin

embedding static assets http caching

Intermediate 6 steps

ruby

class KeyTransformer
  def self.camelize(data)
    new.camelize(data)
  end

Recursively camelizing nested Ruby data

recursion data-transformation pattern-matching

Intermediate 7 steps

python

from django import template
from django.urls import reverse, NoReverseMatch
from django.utils.html import format_html

Active nav-link template tags in Django

template tags url routing active state

Intermediate 7 steps

javascript

import { useReducer, useEffect } from "react";
 
const initialState = { status: "idle", data: null, error: null };

Building a data-fetching hook in React

custom-hooks usereducer data-fetching

Intermediate 9 steps

ruby

module Paginatable
  extend ActiveSupport::Concern
 
  private

A reusable pagination concern in Rails

pagination concerns http-headers

Intermediate 8 steps

php

<?php
 
namespace App\Broadcasting;

Authorizing presence channels in Laravel

broadcasting authorization presence-channels

Intermediate 3 steps

go

package config
 
import (
	"fmt"

A thread-safe config singleton in Go

singleton concurrency environment-variables

Intermediate 7 steps

python

from functools import wraps
import asyncio
 
from fastapi import APIRouter, FastAPI, Request

Per-route request timeouts in FastAPI

decorators async timeouts

Intermediate 6 steps