JavaScript

const x = 5;
const y = 10;

const result = `${x + y}`;
const nested = `Value: ${`${x}` + `${y}`}`;
const expr = `${x}${y}`;

console.log(result);
console.log(nested);
console.log(expr);
console.log(typeof result);

const x = 0.1 + 0.2;
const y = 0.3;

console.log(x === y);
console.log(x.toFixed(1) === y.toFixed(1));
console.log(+x.toFixed(1) === +y.toFixed(1));

const num = 42;
console.log(num.toString(2));
console.log(parseInt('101010', 2));

const multiplier = 3;

function createCounter() {
  let count = 0;
  const multiplier = 5;
  
  return function() {
    count++;
    return count * multiplier;
  };
}

const counter = createCounter();
console.log(counter());
console.log(counter());
console.log(multiplier);

const json = '{"name":"Sarah","age":25,"active":true}';
const obj = JSON.parse(json);

obj.name = "Emma";
obj.age++;

const json2 = JSON.stringify(obj);
const obj2 = JSON.parse(json2);

obj.age = 100;

console.log(obj2.age);

function Vehicle(type) {
  this.type = type;
  this.wheels = 4;
}

Vehicle.prototype.describe = function() {
  return `${this.type} with ${this.wheels} wheels`;
};

const car = new Vehicle('Car');
const bike = Vehicle('Bike');

console.log(car.describe());
console.log(typeof bike);
console.log(globalThis.type);

const x = null;
const y = undefined;
const z = 0;

const result1 = x ?? 'default';
const result2 = y ?? 'default';
const result3 = z ?? 'default';

const combined = result1 ? result2 ? result3 : 'B' : 'C';

console.log(combined);

function Vehicle(type) {
  this.type = type;
}

Vehicle.prototype.wheels = 4;
Vehicle.prototype.getInfo = function() {
  return `${this.type}: ${this.wheels}`;
};

const car = new Vehicle('Car');
const bike = Object.create(car);
bike.type = 'Bike';
bike.wheels = 2;

console.log(car.getInfo() + ' | ' + bike.getInfo());

const obj = { a: 1, b: 2, c: 3 };
Object.defineProperty(obj, 'd', { 
  value: 4, 
  enumerable: false 
});

const entries = Object.entries(obj);
const keys = Object.keys(obj);
const values = Object.values(obj);

console.log(entries.length + keys.length + values.length);