JavaScript Object getOwnPropertyNames() Method

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The Object.getOwnPropertyNames() method in JavaScript is a standard built-in object which returns all properties that are present in a given object except for those symbol-based non-enumerable properties.

Syntax:

Object.getOwnPropertyNames(obj)

Parameters: This method accepts a single parameter as mentioned above and described below:

obj: This parameter holds the object whose enumerable and non-enumerable properties are to be returned.

Return value: This method returns an array of strings that corresponds to the properties found directly in the given object.

Below examples illustrate the Object.getOwnPropertyNames() method in JavaScript:

Example 1: In this example, we will check if an object contains some properties or not using the Object.getOwnPropertyNames() method in JavaScript.

javascript

const gfg = { 
    val1: "Geek1", 
    val2: "Geek2", 
    val3: "Geek3", 
    val4: "Geek4"
}; 
console.log(Object.getOwnPropertyNames(gfg)); 
  
let gfg2 = { val1: 'Geek1', val2: 'Geek2', val3: 'Geek3' }; 
console.log(Object.getOwnPropertyNames(gfg2).sort()); 
  
Object.getOwnPropertyNames(gfg2). 
    forEach(function (val, idx, array) { 
        console.log(val + ': ' + gfg2[val]); 
  
    });

Output:

Array ["val1", "val2", "val3", "val4"]
Array ["val1", "val2", "val3"]
"val1 : Geek1"
"val2 : Geek2"
"val3 : Geek3"

Example 2: In this example, we will check if an object contains some properties or not using the Object.getOwnPropertyNames() method in JavaScript.

javascript

function ParentClass() { } 
ParentClass.prototype.inheritedMethod = function () { }; 
  
function ChildClass() { 
    this.prop = 5; 
    this.method = function () { }; 
} 
ChildClass.prototype = new ParentClass; 
ChildClass.prototype.prototypeMethod = function () { }; 
  
console.log( 
    Object.getOwnPropertyNames( 
        new ChildClass() 
    ) 
); 
  
let my_obj = Object.create({}, { 
    getFoo: { 
        value: function () { return this.foo; }, 
        enumerable: false
    } 
}); 
my_obj.foo = 1; 
  
console.log(Object.getOwnPropertyNames(my_obj).sort());

Output:

Array ["prop", "method"]
Array ["foo", "getFoo"]

We have a complete list of Javascript Object methods, to check those please go through this JavaScript Object Complete Reference article.

Supported Browsers: The browsers supported by Object.getOwnPropertyNames() method are listed below:

Google Chrome 5 and above
Edge 12 and above
Firefox 4 and above
Internet Explorer 9 and above
Opera 12 and above
Safari 5 and above

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