: o.propertyIsEnumerable is not a function
    Object.prototype.propertyIsEnumerable.call(o, "enumerableOwn"); // true
    

Alternatively, you may use [ ` Object.getOwnPropertyDescriptor() ` ](/en-
US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyDescriptor)
instead, which also helps to distinguish between non-existent properties and
actually non-enumerable properties.

js

    
    
    const o = {
      __proto__: null,
      enumerableOwn: "is enumerable",
    };
    
    Object.getOwnPropertyDescriptor(o, "enumerableOwn")?.enumerable; // true
    Object.getOwnPropertyDescriptor(o, "nonExistent")?.enumerable; // undefined
    

##  Specifications

Specification  
---  
[ ECMAScript Language Specification  
#  sec-object.prototype.propertyisenumerable
](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-
object.prototype.propertyisenumerable)  
  
##  Browser compatibility

BCD tables only load in the browser  with JavaScript enabled. Enable
JavaScript to view data.

##  See also

  * [ Enumerability and ownership of properties ](/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties)
  * [ ` for...in ` ](/en-US/docs/Web/JavaScript/Reference/Statements/for...in)
  * [ ` Object.keys() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys)
  * [ ` Object.defineProperty() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty)

##  Help improve MDN

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