Symbol.for()

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.

The Symbol.for() static method searches for existing symbols in a runtime-wide symbol registry with the given key and returns it if found. Otherwise a new symbol gets created in the global symbol registry with this key.

Try it

console.log(Symbol.for("bar") === Symbol.for("bar"));
// Expected output: true

console.log(Symbol("bar") === Symbol("bar"));
// Expected output: false

const symbol1 = Symbol.for("foo");

console.log(symbol1.toString());
// Expected output: "Symbol(foo)"

Syntax

Symbol.for(key)

Parameters

key

String, required. The key for the symbol (and also used for the description of the symbol).

Return value

An existing symbol with the given key if found; otherwise, a new symbol is created and returned.

Description

In contrast to Symbol(), the Symbol.for() function creates a symbol available in a global symbol registry list. Symbol.for() does also not necessarily create a new symbol on every call, but checks first if a symbol with the given key is already present in the registry. In that case, that symbol is returned. If no symbol with the given key is found, Symbol.for() will create a new global symbol.

Examples

Using Symbol.for()

js
Symbol.for("foo"); // create a new global symbol
Symbol.for("foo"); // retrieve the already created symbol

// Same global symbol, but not locally
Symbol.for("bar") === Symbol.for("bar"); // true
Symbol("bar") === Symbol("bar"); // false

// The key is also used as the description
const sym = Symbol.for("mario");
sym.toString(); // "Symbol(mario)"

To avoid name clashes with your global symbol keys and other (library code) global symbols, it might be a good idea to prefix your symbols:

js
Symbol.for("mdn.foo");
Symbol.for("mdn.bar");

Specifications

Specification

ECMAScript® 2027 Language Specification
# sec-symbol.for

Browser compatibility

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This page was last modified on Jul 10, 2025 by MDN contributors.

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Standard built-in objects
Symbol
Constructor
1. Symbol()
Static methods
1. for()
2. keyFor()
Static properties
Instance methods
Instance properties
1. description
Inheritance
Object/Function
Static methods
Static properties
Instance methods
Instance properties
1. __proto__
2. constructor