The power and flexibility of the ServiceNow platform are significantly amplified by its scripting capabilities. GlideScript allows for deep customization and automation, enabling organizations to tailor the platform to their precise needs. However, the effectiveness and longevity of these customizations hinge on the quality of the code. Poorly written GlideScript can lead to performance bottlenecks, increased maintenance overhead, and ultimately, hinder the platform’s value. Understanding and implementing ServiceNow scripting best practices is therefore essential for any organization leveraging the platform extensively. This post explores key principles for writing efficient and maintainable GlideScript, ensuring your ServiceNow environment remains robust and scalable.

The Tangible Impact of Quality GlideScript

The way GlideScript is written has a direct and measurable impact on the health and effectiveness of a ServiceNow instance. Neglecting ServiceNow scripting best practices can lead to several challenges:

• Performance Degradation: Inefficient scripts, especially those running on the client-side or during critical server-side processes, can slow down the entire platform, impacting user experience and operational efficiency.
• Increased Maintenance Costs: Poorly structured and undocumented code is difficult to understand, debug, and modify, leading to higher maintenance costs and longer resolution times for issues.
• Reduced Scalability: Inefficient scripts can hinder the platform’s ability to handle increasing data volumes and user loads, limiting its scalability as the organization grows.
• Higher Risk of Errors: Complex and convoluted code is more prone to errors and unexpected behavior, potentially leading to data inconsistencies or process failures.
• Difficulty in Collaboration: Inconsistent coding styles and lack of documentation make it challenging for multiple developers to collaborate effectively on the same codebase.
• Security Vulnerabilities: Poorly written scripts can sometimes introduce security vulnerabilities if not handled with care.

Therefore, adopting ServiceNow scripting best practices is not just about writing code that works; it’s about building a sustainable and high-performing ServiceNow environment.

Check out our blog on ServiceNow Performance Optimization here – https://kovnow.com/servicenow-performance-optimization/

Essential ServiceNow Scripting Best Practices

Writing efficient and maintainable GlideScript requires adherence to a set of key principles. Here are crucial ServiceNow scripting best practices to incorporate into your development process:

1. Follow Clear and Consistent Coding Standards

Establishing and adhering to consistent coding standards across your development team is fundamental for maintainability and collaboration. This includes:

• Meaningful Naming Conventions: Use clear and descriptive names for variables, functions, and script includes that reflect their purpose.
• Consistent Indentation and Formatting: Employ consistent indentation and formatting to improve code readability.
• Code Comments: Add comments to explain complex logic, the purpose of functions, and any non-obvious implementation details.
• Consistent Structure: Follow a consistent structure for your scripts, making it easier to understand the flow of execution.

2. Write Efficient and Selective Queries

Interacting with the ServiceNow database efficiently is critical for performance. Follow these guidelines for GlideRecord queries:

• Use addQuery() and addEncodedQuery() Effectively: Construct precise queries to retrieve only the necessary records. Avoid querying the entire table and filtering in script.
• Index Your Queries: Ensure that the fields you are querying on are indexed to speed up data retrieval. Regularly review and optimize indexes.
• Use setLimit(): When you only need a specific number of records, use setLimit() to avoid processing unnecessary data.
• Consider hasNext() and next(): When iterating through query results, use the hasNext() and next() methods instead of loading all records into an array.
• Avoid Queries in Loops: Minimize or eliminate database queries within loops, as this can lead to significant performance degradation.

3. Optimize Client-Side Scripting

Client-side scripts directly impact the user experience. Write them with performance in mind:

• Minimize DOM Manipulation: Reduce the number of times you directly manipulate the Document Object Model (DOM), as this can be resource-intensive.
• Use Asynchronous GlideAjax: For server-side calls from the client, use asynchronous GlideAjax to prevent blocking the user interface.
• Optimize UI Policies: Ensure UI Policies are efficient and only execute when necessary. Avoid complex logic in UI Policies if possible.
• Debounce and Throttle Events: For events that fire frequently (e.g., onChange), use debouncing or throttling techniques to limit the number of times your script executes.

4. Handle Errors Gracefully

Robust error handling is essential for preventing script failures and providing informative feedback:

• Use try...catch Blocks: Implement try...catch blocks to gracefully handle potential exceptions in your code.
• Log Errors Effectively: Log errors with sufficient detail to facilitate debugging and troubleshooting.
• Provide User-Friendly Feedback: When errors occur, provide clear and informative messages to the user.

5. Utilize Script Includes for Reusability

Script Includes are a powerful way to encapsulate reusable logic and promote code maintainability:

• Create Functions for Reusable Code: Define functions within Script Includes for code that is used in multiple scripts.
• Call Script Includes: Call functions from Script Includes in your client-side and server-side scripts.
• Choose the Appropriate Script Include Type: Understand the different types of Script Includes (e.g., Client Callable, Ajax) and use them appropriately.

6. Avoid Hardcoding Values

Hardcoding values directly into scripts makes them less flexible and harder to maintain. Instead:

• Use System Properties: Store configuration values in System Properties and retrieve them in your scripts.
• Reference Configuration Tables: Create dedicated configuration tables for more complex settings.

7. Be Mindful of Asynchronous Operations

Understand the behavior and implications of asynchronous operations (e.g., Workflows, Scheduled Jobs, GlideAggregate with callbacks):

• Manage Callbacks Carefully: Ensure callbacks are handled correctly to avoid unexpected behavior.
• Track Asynchronous Processes: Implement mechanisms to track the status and outcome of asynchronous operations when necessary.

8. Test Your Scripts Thoroughly

Thorough testing is crucial for identifying and fixing issues before deploying code to production:

• Unit Testing: Test individual functions and components of your scripts.
• Integration Testing: Test scripts in the context of the larger application flow.
• Use Script Debugger: Leverage the ServiceNow Script Debugger to step through code and identify issues.

9. Document Your Code

Clear and concise documentation is essential for maintainability and collaboration:

• Document Functions: Explain the purpose, parameters, and return values of your functions.
• Document Complex Logic: Provide comments to explain the reasoning behind complex code sections.
• Keep Documentation Up-to-Date: Ensure your documentation is updated whenever you modify your code.

External Link: ServiceNow’s Developer Portal offers comprehensive guidance on GlideScript and best practices: https://developer.servicenow.com/devportal.do

Read our blog on ServiceNow Performance Optimization

The Importance of Skilled ServiceNow Developers

Adhering to these ServiceNow scripting best practices requires a solid understanding of the platform’s architecture, GlideScript syntax, and asynchronous processing. Identifying and retaining developers with these skills is crucial for building robust and scalable ServiceNow solutions. Consulting firms that prioritize hiring and developing talent proficient in efficient scripting practices will be better equipped to deliver high-quality and performant solutions for their clients.

Conclusion: Building a Foundation of Efficient and Maintainable ServiceNow Solutions

Writing efficient and maintainable GlideScript is not just a technical skill; it’s a cornerstone of building a healthy and high-performing ServiceNow environment. By embracing these ServiceNow scripting best practices, organizations can minimize performance issues, reduce maintenance costs, enhance scalability, and foster better collaboration among development teams. Investing in the knowledge and discipline to write clean, efficient, and well-documented code is a strategic imperative for maximizing the long-term value of the ServiceNow platform.