JavaScript Object hasOwnProperty() Method

The hasOwnProperty() method in JavaScript checks if an object has a specific property as its own (not inherited). It returns true if the property exists directly on the object, otherwise false, making it useful for distinguishing own properties from inherited ones.

Syntax

object.hasOwnProperty( prop );

Parameters:

• prop: It holds the name in the form of a String or a Symbol of the property to test.

Return Value:

It returns a Boolean value indicating whether the object has the given property as its own property.

Example 1: In this example, the hasOwnProperty() method checks if the exampleObj contains the properties "height" (which exists) and "breadth" (which doesn't exist). It returns true for "height" and false for "breadth".

let exampleObj = {};
exampleObj.height = 100;
exampleObj.width = 100;

// Checking for existing property
let result1 = exampleObj.hasOwnProperty("height");

// Checking for non-existing property
let result2 = exampleObj.hasOwnProperty("breadth");

console.log(result1);  // true
console.log(result2);  // false

true
false

Example 2: In this example The checkProperty() function creates a Car object and checks if the model property exists (true) and if the wheels property doesn't exist (false) using the hasOwnProperty() method.

function checkProperty() {

    function Car(a, b) {
        this.model = a;
        this.name = b;
    }

    let car1 = new Car("Mazda", "Laputa");

    // Checking for existing property
    result1 = car1.hasOwnProperty("model");

    // Checking for non-existing property
    result2 = car1.hasOwnProperty("wheels");

    console.log(result1);

    console.log(result2);
}
checkProperty()

true
false

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

Supported Browsers:

• Google Chrome
• Firefox
• Edge
• Safari
• Opera

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Article Tags :

• JavaScript
• Web Technologies
• javascript-object
• JavaScript-Methods