const numbers = [1, 2, 3, 4, 5];

const result = numbers
  .filter(n => n % 2 === 0)
  .map(n => n * 2)
  .reduce((acc, n) => acc + n, 0);

console.log(result);

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));

const obj1 = { a: 1, b: 2 };
const obj2 = { b: 3, c: 4 };
const mergedObj = { ...obj1, ...obj2 };
console.log(mergedObj);

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 arr = [3, 8, 12];
const even = (elem) => elem % 2 === 0;

console.log(arr.map(even));

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 user = {
  profile: {
    name: 'Alice',
    settings: {
      notifications: {
        email: true,
        sms: false
      }
    }
  },
  getPreference(type) {
    return this.profile?.settings?.notifications?.[type] ?? 'not configured';
  }
};

const admin = {
  profile: {
    name: 'Admin',
    settings: null
  },
  getPreference: user.getPreference
};

console.log(admin.getPreference('email'));

async function test() {
  console.log('1');
  
  setTimeout(() => {
    console.log('2');
  }, 0);
  
  await Promise.resolve();
  console.log('3');
  
  new Promise(resolve => {
    console.log('4');
    resolve();
  }).then(() => {
    console.log('5');
  });
  
  console.log('6');
}

test();
console.log('7');

'use strict';

function strictModeExample() {
  undeclaredVariable = 10;
  try {
    console.log(undeclaredVariable);
  } catch (e) {
    console.log('Error:', e.message);
  }
}

strictModeExample();

async function test() {
  console.log('1');
  
  setTimeout(() => {
    console.log('2');
  }, 0);
  
  await Promise.resolve();
  console.log('3');
  
  new Promise(resolve => {
    console.log('4');
    resolve();
  }).then(() => {
    console.log('5');
  });
  
  console.log('6');
}

test();
console.log('7');

const str = "  Hello, World!  ";

const result = str
  .trim()
  .split(", ")
  .map((word, i) => {
    if (i % 2 === 0) return word.toUpperCase();
    return word.toLowerCase().replace("!", "@");
  })
  .reverse()
  .join(" | ");

console.log(result);

function Animal(name) {
  this.name = name;
}

Animal.prototype.speak = function() {
  return `${this.name} makes a noise`;
};

function Dog(name) {
  Animal.call(this, name);
}

Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;

Dog.prototype.speak = function() {
  return `${this.name} barks`;
};

const animal = new Animal('Animal');
const dog = new Dog('Rex');

console.log(dog instanceof Animal);

const team = {
  members: ['Alice', 'Bob', 'Charlie'],
  [Symbol.iterator]: function*() {
    let index = 0;
    while(index < this.members.length) {
      yield this.members[index++].toUpperCase();
    }
  }
};

const result = [];
for (const member of team) {
  result.push(member);
}

console.log(result.join('-'));

function processData({ a = 10, b = 20 } = { a: 30 }) {
  console.log(a, b);
}

processData({ a: 5 });
processData();

function highlight(strings, ...values) {
  return strings.reduce((result, str, i) => {
    const value = values[i] ? `<span>${values[i]}</span>` : '';
    return result + str + value;
  }, '');
}

const language = 'JavaScript';
const years = 10;

const result = highlight`I have been coding in ${language} for ${years} years`;
console.log(result);

const str = "  Hello, World!  ";

const result = str
  .trim()
  .split(", ")
  .map((word, i) => {
    if (i % 2 === 0) return word.toUpperCase();
    return word.toLowerCase().replace("!", "@");
  })
  .reverse()
  .join(" | ");

console.log(result);

function mystery(x) {
  return (function(y) {
    return x + y;
  })(x * 2);
}

const result1 = mystery(2);
const result2 = mystery(5);
const result3 = mystery(-1);

console.log(result1, result2, result3);

'use strict';

function strictModeExample() {
  undeclaredVariable = 10;
  try {
    console.log(undeclaredVariable);
  } catch (e) {
    console.log('Error:', e.message);
  }
}

strictModeExample();

class MyClass {
  constructor() {
    this.a = 100;
  }
}
MyClass.prototype.b = 200;
const obj = new MyClass();
delete obj.b;
console.log(obj.a);

const regex = /a/g;
const str = 'banana';
console.log(str.match(regex));