const person = {
  firstName: 'John',
  lastName: 'Doe',
  age: 30,
  getFullName: function() {
    return this.firstName + ' ' + this.lastName;
  }
};

console.log(person.getFullName());

const a = '5';
const b = 5;
const c = 10;

const result1 = a == b;
const result2 = a === b;
const result3 = b < c;
const result4 = b >= c;

console.log(result1, result2, result3, result4);

let a = 5;
let b = a++ + ++a;
console.log(b);

'use strict';

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

strictModeExample();

function* numberGenerator() {
  yield 1;
  yield 2;
  yield 3;
}

const gen = numberGenerator();
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);

const symbol1 = Symbol('symbol');
const symbol2 = Symbol('symbol');

const obj = {};
obj[symbol1] = 'value1';
obj[symbol2] = 'value2';

console.log(obj[symbol1]);

function outerFunction() {
  let x = 10;
  function innerFunction() {
    x += 5;
    console.log(x);
  }
  return innerFunction;
}

const closureFunc = outerFunction();
closureFunc();
closureFunc();