JavaScript is a popular programming language that is widely used for web development and server-side scripting. With the introduction of Java 8, the Nashorn JavaScript engine was included, allowing developers to execute JavaScript code directly on the Java Virtual Machine (JVM). In this blog post, we will explore how to create and manage JavaScript objects in Nashorn.

Table of Contents

• Introduction
• Creating JavaScript Objects
• Accessing Object Properties
• Modifying Object Properties
• Deleting Object Properties
• Conclusion

Introduction

Nashorn provides a seamless integration between JavaScript and Java, making it possible to interact with Java objects from JavaScript and vice versa. JavaScript objects can be created using the new keyword and function constructors. Let’s explore how to create JavaScript objects in Nashorn.

Creating JavaScript Objects

To create a JavaScript object in Nashorn, you can use the new keyword followed by a function constructor. A function constructor is a regular JavaScript function that is used to initialize an object. Here’s an example:

var person = new Object();
person.name = "John";
person.age = 30;
person.sayHello = function() {
    console.log("Hello, my name is " + this.name);
};

In the above example, we create a person object using the new Object() constructor. We then add properties such as name and age, as well as a method sayHello to the object.

Accessing Object Properties

Once an object is created, you can access its properties using either dot notation or bracket notation. Here’s an example:

console.log(person.name);     // Output: John
console.log(person["age"]);   // Output: 30
person.sayHello();            // Output: Hello, my name is John

In the above example, we use dot notation to access the name property and bracket notation to access the age property.

Modifying Object Properties

Object properties in JavaScript are mutable, which means you can modify their values at any time. To modify an object property, simply assign a new value to it. Here’s an example:

person.name = "Jane";
console.log(person.name);   // Output: Jane

In the above example, we modify the name property of the person object and then print the updated value.

Deleting Object Properties

If you no longer need a property in an object, you can delete it using the delete keyword. Here’s an example:

delete person.age;
console.log(person.age);   // Output: undefined

In the above example, we delete the age property from the person object and then try to access it, resulting in undefined.

Conclusion

Nashorn provides an efficient and powerful way to create and manage JavaScript objects within a Java environment. By leveraging the integration between JavaScript and Java, developers can take advantage of the best features of both languages. This opens up a wide array of possibilities for building robust and dynamic applications.

In this blog post, we explored how to create JavaScript objects in Nashorn using function constructors and new keyword. We also looked at how to access, modify, and delete object properties.