const p1 = new Promise((resolve) => {
  console.log("A");
  resolve("B");
});

const p2 = p1.then((val) => {
  console.log(val);
  return "C";
});

p2.then((val) => {
  console.log(val);
});

console.log("D");

function Vehicle(make, model, year) {
  this.make = make;
  this.model = model;
  this.year = year;
  this.describe = function () {
    return `${this.year} ${this.make} ${this.model}`;
  };
}

Vehicle.prototype.age = function (currentYear) {
  return currentYear - this.year;
};

const car = new Vehicle("Toyota", "Supra", 1998);
const bike = new Vehicle("Harley", "Sportster", 2005);

console.log(car.describe());
console.log(bike.age(2025));
console.log(car.constructor === Vehicle);
console.log(Object.getPrototypeOf(car) === Vehicle.prototype);

class EventEmitter {
  #listeners = new WeakMap();
  #registry = new FinalizationRegistry((label) => {
    console.log(`Cleaned up: ${label}`);
  });

  subscribe(target, callback) {
    if (!this.#listeners.has(target)) {
      this.#listeners.set(target, []);
    }
    this.#listeners.get(target).push(callback);
    this.#registry.register(target, target.name ?? "unknown");
  }

  emit(target) {
    const cbs = this.#listeners.get(target);
    if (cbs) cbs.forEach(cb => cb());
  }
}

const emitter = new EventEmitter();
let obj1 = { name: "sensor" };
let obj2 = { name: "timer" };

const ws = new WeakSet([obj1, obj2]);

emitter.subscribe(obj1, () => console.log("sensor fired"));
emitter.subscribe(obj2, () => console.log("timer fired"));
emitter.subscribe(obj1, () => console.log("sensor logged"));

emitter.emit(obj1);

console.log(ws.has(obj1));
obj1 = null;
console.log(ws.has({ name: "sensor" }));

const temperature = {
  celsius: 22,
  [Symbol.toPrimitive](hint) {
    if (hint === 'number') {
      return this.celsius;
    }
    if (hint === 'string') {
      return `${this.celsius}°C`;
    }
    return this.celsius + 273.15;
  }
};

console.log(`Temp: ${temperature}`);
console.log(temperature + 0);
console.log(temperature * 2);
console.log(+temperature);

const a = 10n ** 3n;
const b = BigInt(Number.MAX_SAFE_INTEGER) + 1n;
const c = b + 1n;

console.log(typeof a);
console.log(a === 1000n);
console.log(b === c);
console.log(5n / 2n);

const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args)));

const pipe = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args)));

const double  = x => x * 2;
const addTen  = x => x + 10;
const square  = x => x * x;
const negate  = x => -x;

const transform1 = compose(negate, square, addTen, double);
const transform2 = pipe(double, addTen, square, negate);

const val = 3;

console.log(transform1(val), transform2(val));

const obj = {
  name: "Orion",
  greet() {
    const inner = () => {
      console.log(this.name);
    };
    inner();
  },
  greetRegular: function () {
    const inner = function () {
      console.log(this?.name ?? "undefined");
    };
    inner();
  },
};

obj.greet();
obj.greetRegular();