Code Explainers · highlit

java

public final class Quicksort {
 
    private Quicksort() {
    }

Quicksort with Lomuto partitioning in Java

recursion divide-and-conquer in-place

Intermediate 7 steps

go

package geometry
 
import "fmt"

Implementing fmt.Stringer in Go

interfaces stringer composition

Beginner 5 steps

javascript

function throttle(fn, wait) {
  let lastCall = 0;
  let timeoutId = null;
  let lastArgs = null;

Building a leading-and-trailing throttle

closures rate-limiting timers

Advanced 6 steps

typescript

type Split<S extends string, D extends string> =
  S extends `${infer Head}${D}${infer Tail}`
    ? [Head, ...Split<Tail, D>]
    : [S];

Type-level string parsing in TypeScript

template literal types conditional types recursive types

Advanced 8 steps

javascript

async function* fetchPages(baseUrl, maxPages) {
  let page = 1;
  while (page <= maxPages) {
    const data = await mockFetch(`${baseUrl}?page=${page}`);

Paginated APIs with async generators

async-iterators generators pagination

Advanced 7 steps

javascript

const PENDING = 'pending';
const FULFILLED = 'fulfilled';
const REJECTED = 'rejected';

Building a Promise from scratch

promises state-machine microtasks

Advanced 10 steps

javascript

function delegate(root, eventType, selector, handler) {
  const listener = (event) => {
    let node = event.target;
    while (node && node !== root) {

Event delegation with a clean teardown

event-delegation dom closures

Intermediate 8 steps