Symbol.keyFor()

The Symbol.keyFor(sym) method retrieves a shared symbol key from the global symbol registry for the given symbol.

Symbol.keyFor(sym);

sym

Symbol, required. The symbol to find a key for.

A string representing the key for the given symbol if one is found on the global registry; otherwise, undefined.

var globalSym = Symbol.for('foo'); // create a new global symbol
Symbol.keyFor(globalSym); // "foo"

var localSym = Symbol();
Symbol.keyFor(localSym); // undefined

// well-known symbols are not symbols registered
// in the global symbol registry
Symbol.keyFor(Symbol.iterator) // undefined

• Symbol.for()