What are the differences between javascript and typescript

// JavaScript (Dynamic, runtime checking):
function calculate(price, tax) {
  return price + tax; // If passed strings, accidentally concatenates!
}

// TypeScript (Static compile-time checking):
interface Order {
  price: number;
  tax: number;
}
function calculateStrict(order: Order): number {
  return order.price + order.tax; // Compile error if invalid types passed
}