ServiceNow Script Include Support for Inheritance with Coding Example

Amit Gujarathi · ‎06-06-2023

ServiceNow Script Include Support for Inheritance with Coding Example

Outline of the Article

1. Introduction

2. Understanding ServiceNow Script Includes

2.1 What is a Script Include?

2.2 Benefits of Script Includes

3. Inheritance in ServiceNow Script Includes

3.1 What is Inheritance?

3.2 How Inheritance Works in ServiceNow

3.3 Example of Inheritance in Script Includes

4. Creating a Script Include with Inheritance

4.1 Step 1: Define the Parent Script Include

4.2 Step 2: Define the Child Script Include

4.3 Step 3: Accessing Functions from the Parent Script Include

5. Best Practices for Using Script Includes

5.1 Reusing Code and Promoting Modularity

5.2 Encapsulating Logic

5.3 Unit Testing and Debugging

6. Conclusion

7. FAQs

7.1 Can I use multiple levels of inheritance in Script Includes?

7.2 Are Script Includes limited to server-side code?

7.3 Can Script Includes be used in Client Scripts?

7.4 How do Script Includes improve performance?

7.5 Are there any limitations to using Script Includes?

2. Understanding ServiceNow Script Includes

2.1. What is a Script Include?

A Script Include in ServiceNow is a server-side JavaScript object that encapsulates reusable code and functions. It acts as a container for code that can be accessed and executed from different parts of the platform, such as business rules, script actions, and workflows. Script Includes promote code reuse, improve maintainability, and enhance performance by encapsulating common logic.

2.2. Benefits of Script Includes

Script Includes offer several benefits in ServiceNow development. They provide a modular approach to code organization, allowing developers to separate and manage different functionalities effectively. Some key benefits of using Script Includes are:

Code Reusability: Script Includes enable the reuse of code across different parts of the platform, reducing redundancy and promoting efficient development practices.
Encapsulation of Logic: By encapsulating logic within Script Includes, developers can create reusable modules that perform specific tasks, making code more organized and easier to maintain.
Modularity: Script Includes allow developers to create self-contained modules that can be easily integrated into different workflows and processes, promoting code modularity and scalability.

3. Inheritance in ServiceNow Script Includes

3.1. What is Inheritance?

Inheritance is a fundamental concept in object-oriented programming (OOP) that allows one class to inherit properties and methods from another class. It promotes code reuse and enables the creation of specialized classes based on existing ones. In the context of ServiceNow Script Includes, inheritance allows child Script Includes to inherit code and functions from a parent Script Include.

3.2. How Inheritance Works in ServiceNow

In ServiceNow, Script Includes support single-level inheritance, which means a child Script Include can inherit from only one parent Script Include. When a child Script Include inherits from a parent, it gains access to all the functions and code defined in the parent. This promotes code reuse and ensures consistency across related Script Includes.

3.3. Example of Inheritance in Script Includes

Let's consider an example where we have a parent Script Include called "VehicleScriptInclude" that defines common functions related to vehicles. We can create a child Script Include called "CarScriptInclude" that inherits from the parent and adds specific functions related to cars. By doing so, the "CarScriptInclude" can leverage the code defined in the parent and extend it with car-specific functionality.

// Parent Script Include: VehicleScriptInclude
var VehicleScriptInclude = Class.create();
VehicleScriptInclude.prototype = {
  initialize: function() {},

  getSpeed: function() {
    return "This is the speed of the vehicle.";
  }
};

// Child Script Include: CarScriptInclude
var CarScriptInclude = Class.create();
CarScriptInclude.prototype = Object.extendsObject(VehicleScriptInclude, {
  initialize: function() {
  },

  getCarModel: function() {
    return "This is the car model.";
  }
});

4. Creating a Script Include with Inheritance

4.1. Step 1: Define the Parent Script Include

To create a parent Script Include, we define a JavaScript object and add functions and properties to it. In our example, the parent Script Include is called "VehicleScriptInclude" and contains a function to get the speed of the vehicle.

4.2. Step 2: Define the Child Script Include

Next, we create the child Script Include, "CarScriptInclude," and use the Object.extendsObject function to inherit from the parent Script Include. We also define a function specific to the child Script Include, which retrieves the car model.

4.3. Step 3: Accessing Functions from the Parent Script Include

To access the functions from the parent Script Include in the child Script Include, we use the prototype property. In the example, the child Script Include calls the parent's initialize function using VehicleScriptInclude.prototype.initialize.call(this).

5. Best Practices for Using Script Includes

While using Script Includes in ServiceNow, it's essential to follow best practices to ensure efficient development and maintainable code. Here are some best practices to consider:

5.1. Reusing Code and Promoting Modularity

Script Includes allow developers to encapsulate code and promote reusability. It's essential to identify common functionalities and extract them into reusable Script Includes, ensuring modular code structure.

5.2. Encapsulating Logic

By encapsulating logic within Script Includes, code becomes more manageable and easier to maintain. Encapsulating logic also improves code readability and reduces duplication.

5.3. Unit Testing and Debugging

When working with Script Includes, it's crucial to test and debug code to ensure it performs as expected. Unit testing and debugging help identify and resolve issues early in the development process.

6. Conclusion

ServiceNow Script Includes provide a powerful way to encapsulate and reuse code within the platform. With support for inheritance, developers can create modular and scalable solutions by leveraging existing code and extending it as per specific requirements. By following best practices and utilizing Script Includes effectively, developers can enhance their development process and create efficient and maintainable solutions.

7. FAQs

1. Can I use multiple levels of inheritance in Script Includes?

No, ServiceNow Script Includes support single-level inheritance. A child Script Include can inherit from only one parent Script Include.

2. Are Script Includes limited to server-side code?

Yes, Script Includes are primarily used for server-side code in ServiceNow. They encapsulate server-side logic and can be accessed from various parts of the platform.

3. Can Script Includes be used in Client Scripts?

No, Script Includes are not directly accessible in client-side code, such as Client Scripts. However, you can use GlideAjax or GlideScriptLoader to leverage server-side Script Includes in client-side code.

4. How do Script Includes improve performance?

Script Includes promote code reuse and modularity, leading to more efficient and optimized code. By encapsulating logic in Script Includes, you can reduce redundancy and improve the overall performance of your ServiceNow instance.

5. Are there any limitations to using Script Includes?

Script Includes have certain limitations. They cannot be used as event handlers and do not support related lists. Additionally, Script Includes cannot directly interact with UI elements.

BillMartin · ‎02-16-2025

Hi @Amit Gujarathi ,

Hope you're doing well!

I've put together this live video demo showcasing software architecture patterns, Object-Oriented Programming (OOP) techniques, and how to inherit from multiple base classes using the Object.extendObject() method.

This demonstration provides valuable insights into how ServiceNow APIs and JavaScript work together, helping you better understand their integration and best practices.

I hope you find it enlightening and useful! Let me know if you have any questions or feedback.

Master Good Software Architecture with Object.extendsObject() | A Guide for ServiceNow Developers

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