Intermediate code explainers

rust

use std::fmt;
 
#[derive(Debug)]
pub enum ConfigError {

Building a custom error type in Rust

error-handling enums trait-implementation

Intermediate 9 steps

java

@RestController
@RequestMapping("/api/products")
@RequiredArgsConstructor
public class ProductSearchController {

Binding paged search filters in Spring

data-binding validation pagination

Intermediate 7 steps

python

import os
from dataclasses import dataclass
from functools import lru_cache

Loading typed config from environment variables

configuration environment-variables type-coercion

Intermediate 6 steps

javascript

function createAutocomplete(input, resultsList, { minChars = 2, delay = 300 } = {}) {
  let timer = null;
  let controller = null;

Building a debounced autocomplete widget

debouncing abortcontroller closures

Intermediate 9 steps

rust

use axum::{
    async_trait,
    extract::{rejection::JsonRejection, FromRequest, Request},
    http::StatusCode,

A validating JSON extractor in Axum

extractors validation error-handling

Intermediate 7 steps

java

@DataJpaTest
@Testcontainers
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
class OrderRepositoryIT {

Testing a JPA repository against real Postgres in Spring

integration-testing testcontainers jpa

Intermediate 8 steps

go

package inventory
 
import (
	"encoding/csv"

Parsing CSV into typed structs in Go

csv-parsing error-wrapping type-conversion

Intermediate 8 steps

python

import hashlib
from pathlib import Path

Streaming SHA-256 checksums in Python

hashing file-io streaming

Intermediate 6 steps

ruby

class ContactImporter
  def initialize(rows)
    @rows = rows
  end

Deduplicating contacts with Enumerable#uniq

deduplication normalization enumerable

Intermediate 4 steps

php

<?php
 
namespace App\Database;

Building a fluent SQL query builder in PHP

fluent-interface method-chaining sql

Intermediate 10 steps

rust

use std::fmt;
 
#[derive(Clone, Copy, PartialEq, Eq)]
pub struct Money {

Formatting money with Rust's Display trait

trait-implementation integer-arithmetic enums

Intermediate 10 steps

go

package search
 
import (
	"net/url"

Building a query URL from a Filter struct in Go

url-encoding struct-methods input-validation

Intermediate 8 steps

javascript

import Link from "next/link";
import { prisma } from "@/lib/prisma";
 
const PAGE_SIZE = 20;

A searchable, paginated table as a Next.js Server Component

server-components pagination search

Intermediate 6 steps

python

import ijson
from decimal import Decimal

Streaming JSON aggregation with ijson

streaming json-parsing generators

Intermediate 7 steps

php

<?php
 
namespace App\Http\Controllers;

Time-limited signed download links in Laravel

signed urls authorization file streaming

Intermediate 6 steps

java

public final class ListPartitioner {
 
    private ListPartitioner() {
    }

Splitting a list into fixed-size chunks in Java

generics partitioning streams

Intermediate 8 steps

go

package handlers
 
import (
	"net/http"

Content negotiation in Gin handlers

content-negotiation struct-tags rest-api

Intermediate 4 steps

javascript

import { Suspense } from 'react';
import { getProducts } from '@/lib/api/products';
import { formatPrice } from '@/lib/format';

Streaming a product list with Suspense in Next.js

server-components suspense streaming

Intermediate 8 steps