Symbol.prototype.toString()

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 toString() method of Symbol values returns a string representing this symbol value.

Try it

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

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

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

// console.log(Symbol('foo') + 'bar');
// Expected output: Error: Can't convert symbol to string

Syntax

toString()

Return value

A string representing the specified symbol value.

The Symbol object overrides the toString method of Object; it does not inherit Object.prototype.toString(). For Symbol values, the toString method returns a descriptive string in the form "Symbol(description)", where description is the symbol's description.

The toString() method requires its this value to be a Symbol primitive or wrapper object. It throws a TypeError for other this values without attempting to coerce them to symbol values.

Because Symbol has a [Symbol.toPrimitive]() method, that method always takes priority over toString() when a Symbol object is coerced to a string. However, because Symbol.prototype[Symbol.toPrimitive]() returns a symbol primitive, and symbol primitives throw a TypeError when implicitly converted to a string, the toString() method is never implicitly called by the language. To stringify a symbol, you must explicitly call its toString() method or use the String() function.

Examples

Using toString()

js
Symbol("desc").toString(); // "Symbol(desc)"

// well-known symbols
Symbol.iterator.toString(); // "Symbol(Symbol.iterator)"

// global symbols
Symbol.for("foo").toString(); // "Symbol(foo)"

Implicitly calling toString()

The only way to make JavaScript implicitly call toString() instead of [Symbol.toPrimitive]() on a symbol wrapper object is by deleting the [Symbol.toPrimitive]() method first.

Warning: You should not do this in practice. Never mutate built-in objects unless you know exactly what you're doing.

js
delete Symbol.prototype[Symbol.toPrimitive];
console.log(`${Object(Symbol("foo"))}`); // "Symbol(foo)"

Specifications

Specification

ECMAScript® 2027 Language Specification
# sec-symbol.prototype.tostring

Browser compatibility

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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