#cleanup code explainers

javascript

import { useCallback, useEffect, useRef, useState } from 'react';
 
export function useInfiniteScroll(fetchPage) {
  const [items, setItems] = useState([]);

Building an infinite scroll hook in React

custom-hooks intersection-observer pagination

Advanced 6 steps

javascript

import { useState, useEffect } from "react";
 
export function useUser(userId) {
  const [user, setUser] = useState(null);

How a data-fetching hook works in React

custom-hooks data-fetching abortcontroller

Intermediate 8 steps

typescript

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

A debounced search hook in React

debounce custom-hooks abortcontroller

Intermediate 7 steps

java

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

Java try-with-resources and AutoCloseable

try-with-resources autocloseable resource-management

Intermediate 6 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