Symbol.keyFor()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨September 2015⁩.

TheSymbol.keyFor() static method retrieves a shared symbolkey from the global symbol registry for the given symbol.

Try it

const globalSym = Symbol.for("foo"); // Global symbolconsole.log(Symbol.keyFor(globalSym));// Expected output: "foo"const localSym = Symbol(); // Local symbolconsole.log(Symbol.keyFor(localSym));// Expected output: undefinedconsole.log(Symbol.keyFor(Symbol.iterator));// Expected output: undefined

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 theglobal registry; otherwise,undefined.

Examples

Using keyFor()

const globalSym = Symbol.for("foo"); // create a new global symbolSymbol.keyFor(globalSym); // "foo"const localSym = Symbol();Symbol.keyFor(localSym); // undefined// well-known symbols are not symbols registered// in the global symbol registrySymbol.keyFor(Symbol.iterator); // undefined