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

Syntax

Symbol.keyFor(sym);

Parameters

sym
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.

Examples

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

Specifications

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.
Draft  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support 40 (Yes) 36.0 (36.0) No support No support No support
Feature Android Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support (Yes) 36.0 (36.0) No support No support No support

See also

Document Tags and Contributors

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