JavaScript

CHALLENGE

const config = {
  timeout: 0,
  retries: null,
  host: "",
  port: undefined,
  debug: false,
};

const timeout = config.timeout ?? 3000;
const retries = config.retries ?? 5;
const host = config.host ?? "localhost";
const port = config.port ?? 8080;
const debug = config.debug ?? true;

console.log(timeout, retries, host, port, debug);

CHALLENGE

const a = 9007199254740991n;
const b = BigInt(Number.MAX_SAFE_INTEGER);

console.log(a === b);
console.log(a + 1n);
console.log(typeof a);
console.log(a === 9007199254740991);

CHALLENGE

const obj = {
  name: "Nikola",
  greetArrow: () => {
    return `Hello, ${this?.name ?? "stranger"}!`;
  },
  greetRegular() {
    return `Hello, ${this.name}!`;
  },
  greetNested() {
    const inner = () => `Hi, ${this.name}!`;
    return inner();
  }
};

console.log(obj.greetArrow());
console.log(obj.greetRegular());
console.log(obj.greetNested());

Somewhere in Yerevan 🇦🇲😆

CHALLENGE

const log = [];

const handler = {
  set(target, key, value) {
    log.push(`set:${key}=${value}`);
    target[key] = value;
    return true;
  },
  get(target, key) {
    log.push(`get:${key}`);
    return target[key];
  }
};

const state = new Proxy({}, handler);

state.count = 0;
state.count = state.count + 1;
state.count = state.count + 1;

console.log(log.join(" | "));

CHALLENGE

const inventory = new Map([
  ["sword", { qty: 3, value: 150 }],
  ["shield", { qty: 1, value: 200 }],
  ["potion", { qty: 5, value: 30 }],
]);

const upgraded = new Map(
  [...inventory.entries()]
    .filter(([, item]) => item.value >= 100)
    .map(([key, item]) => [key, { ...item, value: item.value * 2 }])
);

console.log(upgraded.size);
console.log(upgraded.get("sword").value);
console.log(upgraded.has("potion"));
console.log([...upgraded.keys()].join(", "));

CHALLENGE

function makeCounter(start = 0, step = 1) {
  let count = start;
  const history = [];

  return {
    increment() {
      count += step;
      history.push(count);
      return this;
    },
    decrement() {
      count -= step;
      history.push(count);
      return this;
    },
    getHistory: () => history,
    getCount: () => count,
  };
}

const counter = makeCounter(10, 3);
counter.increment().increment().decrement();

console.log(counter.getCount());
console.log(counter.getHistory());

CHALLENGE

const team = {
  name: "Alpha",
  members: ["Carlos", "Diana", "Eve"],

  listMembers() {
    return this.members.map(function (member) {
      return `${this.name}: ${member}`;
    });
  },

  listMembersArrow() {
    return this.members.map((member) => {
      return `${this.name}: ${member}`;
    });
  },
};

console.log(team.listMembers()[0]);
console.log(team.listMembersArrow()[0]);

CHALLENGE

const flags = {
  READ:    0b0001,
  WRITE:   0b0010,
  EXECUTE: 0b0100,
  DELETE:  0b1000,
};

const userPermissions  = flags.READ | flags.WRITE | flags.EXECUTE;
const adminPermissions = userPermissions | flags.DELETE;

const canDelete  = (adminPermissions & flags.DELETE)  !== 0;
const canExecute = (userPermissions  & flags.EXECUTE) !== 0;
const readOnly   = userPermissions   ^ flags.WRITE;

console.log(canDelete, canExecute, readOnly, adminPermissions >> 1);

😱 Bun's Zig-to-Rust porting saga continues, but what about Node...? The Rust-based rewrite of Bun has been merged, though there are questions over the quality of the AI-ported code. Matteo Collina and Luca Maraschi got together to 😉 discuss the story and speculate whether Node could follow...

CHALLENGE

const config = {
  db: { host: "localhost", port: 5432 },
  cache: { ttl: 300 },
};

Object.freeze(config);

config.debug = true;
config.db.port = 9999;
config.cache = { ttl: 600 };

const sealed = Object.seal({ version: "1.0", meta: { build: 42 } });

sealed.version = "2.0";
sealed.author = "devteam";
sealed.meta.build = 99;

console.log(
  config.debug,
  config.db.port,
  config.cache.ttl,
  sealed.version,
  sealed.author,
  sealed.meta.build
);

🤟 An Official Codemod to Migrate from Axios to fetch A codemod (used via npx codemod) that transforms code using Axios to leverage the WHATWG Fetch API, which is now natively available in Node.js. For some reason they don’t link to it in the post, but it’s here if you want to try it out (and here’s the underlying code). Augustin Mauroy