JavaScript

CHALLENGE

let count = 0;
const inc = () => (count += 1, count);
const a = 0 || inc();
const b = null ?? inc();
const c = a && inc();
const d = b?.toString() || inc();
console.log(a, b, c, d, count);

CHALLENGE

const a = [] + [];
const b = [] + {};
const c = {} + [];
const d = 1 + "1" - 1;
console.log(a, b, c, d);

CHALLENGE

function Timer() {
  this.seconds = 0;
  this.tick = () => { this.seconds++; };
  this.tickRegular = function () { this.seconds++; };
}

const t = new Timer();
const { tick, tickRegular } = t;
tick();

let regularResult;
try {
  tickRegular();
  regularResult = 'no error';
} catch (e) {
  regularResult = e instanceof TypeError;
}

console.log(t.seconds, regularResult);

CHALLENGE

const base = {
  get value() {
    return this._value ?? 'default';
  },
  set value(v) {
    this._value = v;
  }
};

const derived = Object.create(base);
derived.value = 'hello';

const another = Object.create(base);

console.log(derived.value, another.value, derived.hasOwnProperty('_value'));

CHALLENGE

class Base {
  #value = 0;
  get value() { return this.#value; }
  set value(v) { this.#value = v * 2; }
}
class Derived extends Base {
  get value() { return super.value + 1; }
  set value(v) { super.value = v + 10; }
}
const d = new Derived();
d.value = 5;
console.log(d.value, d.value = 100, d.value);

🌲 A Recap of Node.js Interactive 2026 Node.js Interactive returned for the first time since 2019 as part of this month's RenderATL event with Node contributors and invited speakers tackling Node's near-term roadmap in areas like AI, supply chain security, WinterCG becoming Ecma TC55, work on QUIC and HTTP/3 support, and Node's move to one major release a year. Aviv Keller

👀 Uppy 6.0: A Modular JavaScript File Uploader Resumable uploads from disk, Dropbox or GDrive, with wrappers for React, Vue, Svelte & Angular. This version focuses on clean-up, with a rewritten S3 plugin and fewer packages to manage. Transloadit

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CHALLENGE

function createCounters() {
  const counters = [];
  for (let i = 0; i < 3; i++) {
    let count = 0;
    counters.push(() => {
      count += i;
      return count;
    });
  }
  return counters;
}

const counters = createCounters();
const first = counters.map(fn => fn()).join(',');
const second = counters.map(fn => fn()).join(',');
console.log(first, second);

👀 htmx 4.0 has landed, the first major release in two years, with lots of changes. It remains a neat way to add interactivity to server-rendered pages without reaching for a frontend framework.

CHALLENGE

class Timer {
  #ticks = 0;
  tick = () => {
    this.#ticks++;
    return this.#ticks;
  };
  reset() {
    this.#ticks = 0;
    return this.#ticks;
  }
}

const t = new Timer();
const { tick, reset } = t;
let result;
try {
  result = reset();
} catch (e) {
  result = e.constructor.name;
}
console.log(tick(), tick(), result);

⛽️ Drydock: Diff Your npm Tarballs Before You Publish From a Preact core team member comes a tool to diff built npm tarballs against the last published version, flagging install scripts, network access and new binaries. It can then gate your Actions publish job or watch npm's new staged publishing flow. Jovi De Croock