JS Practice — Built-in Objects

Symbol.keyFor() — returns key for global symbol

📖 Usage Example

const s = Symbol.for('hello')
Symbol.keyFor(s)   // → 'hello'

Symbol.keyFor() reverses Symbol.for() — it returns the string key used to register a global symbol.

Symbol.keyFor(sym)

Symbol.keyFor(sym) returns the string key used to register a symbol in the global registry, or undefined for local symbols.

Challenge: Verify that Symbol.keyFor(Symbol.for('hello')) === 'hello'.

💡 Hints (1)