A Function object's read-only name property indicates the function's name as specified when it was created, or it may be rather anonymous or ''(an empty string) for functions created anonymously.

Property attributes of
Writable no
Enumerable no
Configurable yes

Note that in non-standard, pre-ES2015 implementations the configurable attribute was false as well.

JavaScript compressors and minifiers

Warning: Be careful when using and source code transformations, such as those carried out by JavaScript compressors (minifiers) or obfuscators. These tools are often used as part of a JavaScript build pipeline to reduce the size of a program prior to deploying it to production. Such transformations often change a function's name at build-time.

Source code such as:

function Foo() {};
let foo = new Foo();

if ( === 'Foo') {
  console.log("'foo' is an instance of 'Foo'");
} else {

may be compressed to:

function a() {};
let b = new a();
if ( === 'Foo') {
  console.log("'foo' is an instance of 'Foo'");
} else {

In the uncompressed version, the program runs into the truthy-branch and logs "'foo' is an instance of 'Foo'". Whereas, in the compressed version it behaves differently, and runs into the else-branch. If you rely on, like in the example above, make sure your build pipeline doesn't change function names, or don't assume a function to have a particular name.


Function statement name

The name property returns the name of a function statement.

function doSomething() {}; // "doSomething"

Function constructor name

Functions created with the syntax new Function(...) or just Function(...) create Function objects and their name is "anonymous".

(new Function).name; // "anonymous"

Anonymous function expression

Anonymous function expressions that were created using the keyword function or arrow functions would have ""(an empty string) as their name.

(function() {}).name; // ""
(() => {}).name; // ""

Inferred function names

Variables and methods can infer the name of an anonymous function from its syntactic position (new in ECMAScript 2015).

let f = function() {};
let object = {
  someMethod: function() {}

console.log(; // "f"
console.log(; // "someMethod"

You can define a function with a name in a function expression:

let object = {
  someMethod: function object_someMethod() {}
console.log(; // logs "object_someMethod"

try { object_someMethod } catch(e) { console.log(e); }
// ReferenceError: object_someMethod is not defined

The name property is read-only and cannot be changed by the assigment operator:

 let object = {
  // anonymous
  someMethod: function() {}
}; = 'otherMethod';
console.log(; // someMethod

To change it, use Object.defineProperty().

Shorthand method names

var o = {
};; // "foo";

Bound function names

Function.bind() produces a function whose name is "bound " plus the function name.

function foo() {};
foo.bind({}).name; // "bound foo"

Function names for getters and setters

When using get and set accessor properties, "get" or "set" will appear in the function name.

let o = {
  get foo(){},
  set foo(x){}

var descriptor = Object.getOwnPropertyDescriptor(o, "foo");; // "get foo"; // "set foo";

Function names in classes

You can use to check the "class" of an object (but be sure to read the warnings below):

function Foo() {}  // ES2015 Syntax: class Foo {}

var fooInstance = new Foo();
console.log(; // logs "Foo"

Warning: The script interpreter will set the built-in property only if a function does not have an own property called name (see section 9.2.11 of the ECMAScript2015 Language Specification). However, ES2015 specifies the static keyword such that static methods will be set as OwnProperty of the class constructor function (ECMAScript2015, +

Therefore we can't obtain the class name for virtually any class with a static method property name():

class Foo {
  constructor() {}
  static name() {}

With a static name() method no longer holds the actual class name but a reference to the name() function object. Above class definition in ES2015 syntax will behave in Chrome or Firefox similar to the following snippet in ES5 syntax:

function Foo() {}
Object.defineProperty(Foo, 'name', { writable: true }); = function() {};

Trying to obtain the class of fooInstance via won't give us the class name at all but a reference to the static class method. Example:

let fooInstance = new Foo();
console.log(; // logs function name()

You may also see from the ES5 syntax example that in Chrome or Firefox our static definition of becomes writable. The built-in definition in the absence of a custom static definition is read-only: = 'Hello';
console.log(; // logs "Hello" if class Foo has a static name() property but "Foo" if not.

Therefore you may not rely on the built-in property to always hold a class's name.

Symbols as function names

If a Symbol is used a function name and the symbol has a description, the method's name is the description in square brackets.

let sym1 = Symbol("foo");
let sym2 = Symbol();
let o = {
  [sym1]: function(){},
  [sym2]: function(){}

o[sym1].name; // "[foo]"
o[sym2].name; // ""


ECMAScript (ECMA-262)
The definition of 'name' in that specification.

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
nameChrome Full support 15Edge Full support 14Firefox Full support 1IE No support NoOpera Full support 10.5Safari Full support 6WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 11Safari iOS Full support 6Samsung Internet Android Full support 1.0nodejs Full support Yes
Configurable: trueChrome Full support 43Edge Full support 14Firefox Full support 38IE No support NoOpera Full support 30Safari No support NoWebView Android Full support 43Chrome Android Full support 43Firefox Android Full support 38Opera Android Full support 30Safari iOS No support NoSamsung Internet Android Full support 4.0nodejs ?
Inferred names on anonymous functionsChrome Full support 51Edge Partial support 14
Partial support 14
Notes Names for functions defined in a dictionary are properly assigned; however, anonymous functions defined on a var/let variable assignment have blank names.
Firefox Full support 53IE No support NoOpera Full support 38Safari Full support 10WebView Android Full support 51Chrome Android Full support 51Firefox Android Full support 53Opera Android Full support 41Safari iOS Full support 10Samsung Internet Android Full support 5.0nodejs ?


Full support
Full support
Partial support
Partial support
No support
No support
Compatibility unknown
Compatibility unknown
See implementation notes.
See implementation notes.

See also