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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

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
keyForChrome Full support 40Edge Full support 12Firefox Full support 36IE No support NoOpera Full support YesSafari Full support 9WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 36Opera Android Full support YesSafari iOS Full support 9Samsung Internet Android Full support Yesnodejs Full support Yes


Full support  
Full support
No support  
No support

See also