EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 600+ Courses All in One Bundle
  • Login

JavaScript hasOwnProperty()

Home » Software Development » Software Development Tutorials » JavaScript Tutorial » JavaScript hasOwnProperty()

JavaScript hasOwnPropert

Definition of JavaScript hasOwnProperty()

JavaScript HasOwnProperty is a function which helps us in validating if the mentioned property is its own property or not. This also helps in understanding if the property is inherited or is created on its own or notwith the stored key value pairs and the array like data types which may contain many useful methods.

Syntax:

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

object.hasOwnProperty( property )

Above syntax helps us in getting the details about the property which is sent as a parameter. The property a parameter which keeps the name of the property in the way of a string or a symbol is used and is used to test the property.

It will return a Boolean value,which if true will indicate that the property is its own property and false if it is not its own property.

How does JavaScript hasOwnProperty Work?

Let us check a small piece of code which will help us understand the working of this function better.

const object1 = {};
object1.prop1 = 40;
console.log(object1.hasOwnProperty('prop1'));
console.log(object1.hasOwnProperty(prop2));

The above code has a constant object defined. This object is created and has a property prop1 which has the value as 40. When we use the function object.hasOwnProperty we first send the prop1 property. It finds that this property is present and is its own property and was created for object1. It will return true as soon as it finds that this property belongs to the specified object. The second property when it checks the object and properties, it does not find it and will return false as it does not have this property related to object1. Hence it will return false for the second property as it will not find the property2 associated with object1. It is not the own property of the object and hence it will return a false.

Examples of JavaScript hasOwnProperty()

Following are the examples are given below:

Example #1

Checking the properties which belong to a particular object.

Code:

<!DOCTYPE html>
<html>
<head>
<title>
JavaScript | hasOwnProperty() Method which finds the properties for particular object
</title>
</head>
<body>
<h1 style="color: green">
EduCBA - The Education Site
</h1>
<b>
hasOwnProperty() method in JavaScript
</b>
<p>
Click on the button so that you can find it the property belongs to specified object
</p>
<p>Output for own property:
<span class="objProp"></span>
</p>
<p>Output for not own property:
<span class="nonObjProp"></span>
</p>
<button onclick="checkProperty()">
Validate the properties to which they belong
</button>
<script type="text/javascript">
function checkProperty() {
let exObj = {};
exObj.height = 100;
exObj.width = 100;
// This will check the property which belongs to the object
res1 = exObj.hasOwnProperty("height");
// This will check the property which does not belongs to the object
res2 = exObj.hasOwnProperty("breadth");
document.querySelector(".objProp").textContent
= res1;
document.querySelector(".nonObjProp").textContent
= res2;
}
</script>
</body>
</html>

Popular Course in this category
JavaScript Training Program (39 Courses, 23 Projects, 4 Quizzes)39 Online Courses | 23 Hands-on Projects | 225+ Hours | Verifiable Certificate of Completion | Lifetime Access | 4 Quizzes with Solutions
4.5 (5,750 ratings)
Course Price

View Course

Related Courses
Angular JS Training Program (9 Courses, 7 Projects)Vue JS Training (1 Courses, 3 Project)

We have created two classes objProp and nonObjProp. We have used then created a function which helps us in checking the property if it belongs to the object which is corresponding to it. It checks the correspondence with the properties and objects. We have created an object exObj which will store the Boolean result. We store it in res1 and res2 which are objects of the result. We use the function exObj to check if the property is related with this object.The res variables store these values, that is the Boolean values. Ideally the first result should be true and the second result should be false. Please check the below screenshot to get the result.

JavaScript hasOwnProperty()-1.1

This will be the output of the above code. Once you click on the Validate button you should see the output for the properties which belong, and which do not belong. Check the below output once you click the button.

JavaScript hasOwnProperty()-1.2

Example #2

Checking properties of objects when the properties are null or undefined

The below example helps in understanding if the functioning when the property has null value or an undefined value.

Code:

<!DOCTYPE html>
<html>
<head>
<title>
JavaScript | hasOwnProperty() Method
</title>
</head>
<body>
<h1 style="color: green">
EduCBA - The Education Site
</h1>
<b>
hasOwnProperty() method in JavaScript
</b>
<p>
Click on the button so that you can find it the property belongs to specified object
</p>
<p>Output for own property:
<span class="objProp"></span>
</p>
<p>Output for not own property:
<span class="nonObjProp"></span>
</p>
<button onclick="checkProperty()">
Validate the properties to which they belong
</button>
<script type="text/javascript">
function checkProperty() {
let exObj = {};
exObj.propOne = null;
exObj.propTwo = undefined;
// Checking for property when it is null
res1 = exObj.hasOwnProperty("propOne");
// Checking for property when it is undefined
res2 = exObj.hasOwnProperty("propTwo");
document.querySelector(".objProp").textContent
= res1;
document.querySelector(".nonObjProp").textContent
= res2;
}
</script>
</body>
</html>

In the above example we have defined an object exObj. We created two properties propOne and propTwo who have defined values as null and undefined.We have also created the headers which are usually present in a JavaScript code. The checkProperty function has two properties as mentioned earlier. They both are defined against the object exObj. They belong to this object. We will see if these properties having null value or undefined value makes some difference or not. The res1 and res2 are variables which will store the result for these two properties. These will be Boolean values as told earlier. We are then printing these values on the screen which helps us in getting the result on screen. Let us check the output and observe the result when null value is defined. Below will be the output which will be displayed when the program is run.

JavaScript hasOwnProperty()-1.3

When you click on the Validate button you will see the below result.

JavaScript hasOwnProperty()-1.4

If you observe you will see that both the properties have same value as true.

This is because though the value of these properties are null and undefined they belong to the object specified. It makes the property a part of the object and hence the function will return the result as true.

Conclusion

The JavaScript HasOwnProperty() is hence a function which helps us in understanding if the property belongs to an object or not. It returns Boolean value as a result. This property helps us in understanding better with which belong to an object or not.

Recommended Articles

This is a guide to JavaScript hasOwnProperty(). Here we also discuss the definition and syntax of javascript hasownproperty() along with different examples and its code implementation. You may also have a look at the following articles to learn more –

  1. React Native Swift
  2. React Native vs Swift
  3. Swift Operators
  4. Swift vs Objective C

All in One Software Development Bundle (600+ Courses, 50+ projects)

600+ Online Courses

50+ projects

3000+ Hours

Verifiable Certificates

Lifetime Access

Learn More

0 Shares
Share
Tweet
Share
Primary Sidebar
JavaScript Tutorial
  • Functions
    • JavaScript String Functions
    • JavaScript String Length
    • JavaScript split String
    • JavaScript Math Functions
    • Recursive Function in JavaScript
    • Regular Expressions in JavaScript
    • JavaScript Arrow Function
    • JavaScript Date Function
    • Match Function in Javascript
    • Replace Function in JavaScript
    • JavaScript Call Function
    • JavaScript Pass By Value
    • split() Function in JavaScript
    • reduce() Function JavaScript
    • JavaScript String replace
    • JavaScript Compare Strings
    • JavaScript Sleep
    • JavaScript toLowercase()
    • JavaScript String to Float
    • JavaScript String to Number
    • JavaScript String to int
    • JavaScript Object to String
    • JavaScript Convert to JSON
    • JavaScript Append
    • Javascript Array to String
    • Javascript Nested Functions
    • Set in JavaScript
    • Vectors in JavaScript
    • Javascript Anonymous Function
    • sign() in JavaScript
    • isNaN() JavaScript
    • Slice() Method in JavaScript
    • Javascript void
    • endsWith() in JavaScript
    • trim() Function in JavaScript
    • JavaScript typeof
    • JavaScript indexOf()
    • JavaScript encodeURI()
    • JavaScript Random
    • JavaScript z-index
    • JavaScript Absolute Value
    • JavaScript Closure
    • Javascript Prototype
    • JavaScript Date parse
    • JavaScript Parse String
    • JavaScript undefined
    • JavaScript FileReader
    • JavaScript Style visibility
    • JavaScript sleep Function
    • JavaScript forEach()
    • JavaScript keys()
    • JavaScript find() 
    • JavaScript values()
    • JavaScript Counter
    • JavaScript Countdown
    • JavaScript instanceof
    • JavaScript Delay
    • JavaScript Default Value
    • JavaScript concat String
    • JavaScript Document Object Model
    • Unshift JavaScript
    • JavaScript Callback Function
    • JavaScript hasOwnProperty()
    • JavaScript UUID
    • JSON Parser
    • JSON Array of Strings
    • JavaScript JSON to string
    • JavaScript Uppercase
    • JavaScript Namespace
    • JavaScript Range
    • JavaScript JSON
    • JavaScript exec()
    • JavaScript test()
    • JavaScript Self Invoking Functions
    • JSON Stringify Pretty
    • JavaScript findIndex()
    • JavaScript entries()
    • JavaScript join()
    • JavaScript lastIndexOf()
    • JavaScript every()
    • JavaScript getElementById()
    • JavaScript getElementsByName()
    • JavaScript getElementsByTagName()
    • JavaScript getElementsByClassName()
    • JavaScript Animation
    • JavaScript Minify
  • Basic
    • Introduction To JavaScript
    • What is JavaScript
    • What Javascript Can Do
    • Uses of JavaScript
    • How JavaScript Works
    • Is Javascript Case Sensitive
    • Is Javascript Object Oriented
    • Features of JavaScript
    • Careers in JavaScript
    • How to Install JavaScript
    • Best Javascript Frameworks
    • JavaScript MVC Frameworks
    • JavaScript Tools
    • What is JSON
    • What is Redux
    • What is ES6
    • Uses of React JS
    • How Analytics.JS Works
    • JavaScript Compilers
    • Java and JavaScript
    • JavaScript Literals
    • Variables in JavaScript
    • JavaScript Global Variable
    • JavaScript Keywords
    • Arithmetic in JavaScript
    • String in JavaScript
    • Pointers in JavaScript
    • Primitive Data Types in JavaScript
    • JavaScript console log
    • Object in JavaScript
    • JavaScript Enum
    • Arithmetic in JavaScript
    • Assignment Operator in JavaScript
    • JavaScript Modules
    • Cheat Sheet JavaScript
    • NPM Alternatives
  • Objects
    • JavaScript Objects
    • JavaScript History Object
    • JavaScript Object Notation
    • JavaScript Map Object
    • JavaScript Date Object
    • JavaScript Window Object
    • JavaScript Object Constructors
    • JavaScript Clone Object
    • JavaScript Object.assign()
    • JavaScript object.is()
  • Operators
    • Arithmetic Operators in JavaScript
    • JavaScript Assignment Operators
    • Logical Operators in JavaScript
    • Comparison Operators in JavaScript
    • Bitwise Operators in JavaScript
    • Ternary Operator JavaScript
    • Boolean Operators in JavaScript
    • JavaScript Boolean()
    • Unary Operators in JavaScript
    • JavaScript Number
    • JavaScript Floating
    • JS Operator Precedence
  • Control statements
    • Control Statement in JavaScript
    • Conditional Statements in JavaScript
    • Break Statement in JavaScript
    • Continue in JavaScript
    • Switch Statement in JavaScript
    • Case Statement in JavaScript
    • JavaScript if Statement
    • Nested if in JavaScript
    • JavaScript elseIf
  • Loops
    • For Loop in JavaScript
    • While Loop in JavaScript
    • Do While Loop in JavaScript
    • Nested Loop in JavaScript
  • Array
    • Arrays in JavaScript
    • Multi-Dimensional Array in JavaScript
    • Associative Array in JavaScript
    • JavaScript Declare Array
    • Arrays Methods in JavaScript
    • JavaScript Loop Array
    • String Array in JavaScript
    • JavaScript Get Array Length
    • JavaScript Merge Arrays
    • JavaScript Array Sort
    • JavaScript Array Push
    • JavaScript Iterate Array
    • JavaScript Empty Array
    • JavaScript Array Concat
    • Dynamic Array in JavaScript
    • JavaScript subarray()
    • JavaScript Array Filter
    • JavaScript Nested Array
    • JavaScript Flatten Array
    • JavaScript Array map()
    • JavaScript Array includes()
    • JavaScript Array Contain
    • JavaScript Array Slice
    • JavaScript Copy Array
    • Javascript Sum Array
    • JavaScript reverse Array
    • JSON Parse Array
  • Sorting
    • Sorting Algorithms in JavaScript
    • Insertion Sort in JavaScript
    • Merge Sort in JavaScript
    • Quick Sort in JavaScript
    • Bubble Sort in JavaScript
    • pop() in JavaScript
    • push() in JavaScript
  • Events
    • JavaScript Events
    • JavaScript Event Handler
    • JavaScript Keyboard Events
    • JavaScript Mouse Events
    • JavaScript mousemove
    • JavaScript mousedown
    • JavaScript onchange
    • JavaScript onmouseout
    • JavaScript Onkeydown
    • JavaScript onsubmit
    • JavaScript Form Events
    • JavaScript Window Events
    • JavaScript Custom Events
    • JavaScript Alert
    • JavaScript Confirm
    • JavaScript onclick Alert
    • JavaScript Apply
    • JavaScript onblur
    • JavaScript onkeyup
    • JavaScript onfocus
  • Advanced
    • Constructor in JavaScript
    • Inheritance in JavaScript
    • Polymorphism in JavaScript
    • JavaScript Static Method
    • Navigator in JavaScript
    • Abstract Classes in JavaScript
    • keyword in JavaScript
    • Overriding in JavaScript
    • JavaScript Grid
    • JavaScript innerText
    • Cookies in JavaScript
    • Delete Cookie in JS
    • Encapsulation in JavaScript
    • JavaScript Parent Node
    • Javascript Remove Element
    • Errors in JavaScript
    • Forms in JavaScript
    • JavaScript Validator
    • JavaScript Form Validation
    • Email Validation in JavaScript
    • Hamburger Menu JavaScript
    • JavaScript Date Formats
    • JavaScript Number Format
    • JavaScript Debugger
    • JavaScript Stack
    • Queue in JavaScript
    • parseFloat in JavaScript
    • Javascript innerHTML
    • JavaScript setInterval
    • JavaScript Popup Box
    • JavaScript Message Box
    • Lightbox in JavaScript
    • Javascript Design Patterns
    • addEventListener JavaScript
    • Timer in JavaScript
    • JavaScript setTimeout
    • JavaScript clearTimeout()
    • JavaScript String Format
    • JavaScript Scroll to Top
    • JavaScript Function Declaration
    • File Handling in JavaScript
    • JavaScript parseInt
    • JavaScript prompt
    • JavaScript Set Class
    • JavaScript Try Catch
    • Javascript Throw Exception
    • Finally in JavaScript
    • JavaScript Get Element by Class
    • JavaScript Obfuscator
    • Disable JavaScript
    • SetAttribute JavaScript
    • JavaScript Cursor
    • LinkedList in JavaScript
    • JavaScript WeakMap
    • JavaScript DOM
    • JavaScript defer
    • JavaScript Promise
    • JavaScript Refresh Page
    • JSON.stringify JavaScript
    • JavaScript IIFE
  • Programs
    • Patterns in JavaScript
    • Reverse in JavaScript
    • Palindrome in JavaScript
    • Factorial Program in JavaScript
    • Fibonacci Series In JavaScript
    • Square Root in JavaScript
    • Prime Number in JavaScript
    • Armstrong Number in JavaScript
    • Random Number Generator in JavaScript
    • Reverse String in JavaScript
    • JavaScript Random String
    • Functional Programming in JavaScript
  • Interview Questions
    • Javascript Interview Questions
    • JSON Interview Questions
    • JS Interview Questions

Related Courses

JavaScript Certification Training

Angular JS Certification Training

Vue JS Training

Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Java Tutorials
  • Python Tutorials
  • All Tutorials
Certification Courses
  • All Courses
  • Software Development Course - All in One Bundle
  • Become a Python Developer
  • Java Course
  • Become a Selenium Automation Tester
  • Become an IoT Developer
  • ASP.NET Course
  • VB.NET Course
  • PHP Course

© 2020 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

*Please provide your correct email id. Login details for this Free course will be emailed to you
Book Your One Instructor : One Learner Free Class

Let’s Get Started

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA Login

Forgot Password?

EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

Special Offer - JavaScript Certification Training Learn More