W3cubDocs

/JavaScript

Symbol.keyFor()

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

Try it

Syntax

js
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()

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

const 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 compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
keyFor 40 12 36 27 9 40 36 27 9 4.0 40 1.0 0.12.0

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/keyFor