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Symbol.keyFor

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

Using keyFor

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

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
keyFor 40 12 36 No 27 9
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
keyFor 40 40 36 27 9 4.0
Server
Node.js
keyFor 0.12

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/keyFor