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




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

Return value

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


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Symbol.keyFor' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Symbol.keyFor' in that specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support40 Yes36 No Yes9
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes36 Yes9 Yes

See also

Document Tags and Contributors

 Contributors to this page: wbamberg, fscholz, jameshkramer, nmve, kdex, eduardoboucas, steelbrain
 Last updated by: wbamberg,