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();

const operations = {
  add: (a, b) => a + b,
  subtract: (a, b) => a - b,
  multiply: (a, b) => a * b,
  divide: (a, b) => b !== 0 ? a / b : null,
};

const pipeline = (...fns) => (value) => fns.reduce((acc, fn) => fn(acc), value);

const double  = (x) => operations.multiply(x, 2);
const addTen  = (x) => operations.add(x, 10);
const halve   = (x) => operations.divide(x, 2);
const subtractThree = (x) => operations.subtract(x, 3);

const transform = pipeline(double, addTen, halve, subtractThree);

console.log(transform(5));

"use strict";

function createCounter() {
  let count = 0;

  return {
    increment() { count++; },
    getCount() { return count; },
    reset: function() { count = 0; }
  };
}

const counter = createCounter();
counter.increment();
counter.increment();
counter.increment();

const { getCount, reset } = counter;

try {
  reset();
  console.log("After reset:", counter.getCount());
} catch (e) {
  console.log("Error:", e.message);
}

console.log("Direct call:", counter.getCount());

const obj = {
  name: "Quantum",
  regular: function () {
    return this.name;
  },
  arrow: () => {
    return this?.name;
  },
  nested: function () {
    const inner = () => this.name;
    return inner();
  },
};

console.log(obj.regular());
console.log(obj.arrow());
console.log(obj.nested());

const curry = (fn) => {
  const arity = fn.length;
  return function curried(...args) {
    if (args.length >= arity) {
      return fn(...args);
    }
    return (...moreArgs) => curried(...args, ...moreArgs);
  };
};

const volume = (l, w, h) => l * w * h;
const curriedVolume = curry(volume);

const withLength5 = curriedVolume(5);
const withLength5Width3 = withLength5(3);

console.log(typeof withLength5);
console.log(typeof withLength5Width3);
console.log(withLength5Width3(4));
console.log(curriedVolume(2)(6)(7));

function highlight(strings, ...values) {
  return strings.reduce((result, str, i) => {
    const value = values[i - 1];
    const formatted =
      typeof value === "number"
        ? `[${value * 2}]`
        : `<${String(value).toUpperCase()}>`;
    return result + formatted + str;
  });
}

const language = "javascript";
const year = 2015;
const feature = "templates";

const output = highlight`Language: ${language}, introduced in ${year}, feature: ${feature}!`;
console.log(output);

const handler = {
  get(target, prop, receiver) {
    if (prop in target) {
      return Reflect.get(target, prop, receiver) * 2;
    }
    return `Missing: ${prop}`;
  },
  set(target, prop, value) {
    if (typeof value !== "number") {
      throw new TypeError("Only numbers allowed");
    }
    return Reflect.set(target, prop, Math.abs(value));
  },
};

const store = new Proxy({ gold: 10, silver: 5 }, handler);

store.bronze = -42;

console.log(store.gold);
console.log(store.bronze);
console.log(store.platinum);

function* range(start, end) {
  while (start < end) {
    yield start++;
  }
}

function* evens(iter) {
  for (const val of iter) {
    if (val % 2 === 0) yield val;
  }
}

function* take(n, iter) {
  let count = 0;
  for (const val of iter) {
    if (count++ >= n) return;
    yield val;
  }
}

function* pipeline() {
  yield* take(3, evens(range(1, 20)));
  yield* take(2, range(10, 15));
}

const result = [...pipeline()];
console.log(result);

const delay = (ms, val) => new Promise(res => setTimeout(res, ms, val));

const p1 = delay(300, "alpha");
const p2 = Promise.reject("network error");
const p3 = delay(100, "gamma");
const p4 = Promise.reject("timeout");

Promise.allSettled([p1, p2, p3, p4]).then(results => {
  const summary = results.map(r =>
    r.status === "fulfilled"
      ? `ok:${r.value}`
      : `fail:${r.reason}`
  );
  console.log(summary.join(" | "));
});