JS Practice — Built-in Objects

Interface — Union Type Parser

📖 Usage Example

type Input = string | number
function toString(x: Input): string {
  return typeof x === 'string' ? x : x.toString()
}

A union type A | B accepts either type; narrowing with typeof enables type-specific operations.

Union Types: parseValue

Challenge: Implement parseValue(input) that converts a string to its native JS type:

parseValue('42')     // → 42
parseValue('true')  // → true

💡 Hints (1)