Legacy Systems in Finance: How Our Team is Driving Change with Angular and TypeScript
Modernizing legacy systems in finance is a multi-faceted challenge that demands a strategic approach to overcome outdated technology limitations, technical debt, and compliance requirements. Before diving deep into how Typescript & Angular has helped our team for facilitating modernization, here’s an overview of the main challenges of using legacy systems:
Outdated Technology Stack
Legacy systems often rely on outdated programming languages, databases, and frameworks that are no longer actively supported or optimized for current business needs. These technologies are not optimized for modern web and mobile use, leading to poor user experience and higher maintenance costs.
The lack of modern development tools and practices such as CI/CD (Continuous Integration and Continuous Deployment), automated testing, or modern frameworks creates a slow development cycle, delaying updates or bug fixes.
Technical Debt and Code Complexity
Legacy systems tend to accrue significant technical debt due to years of accumulated patches, hotfixes, and ad-hoc updates. This results in a codebase that’s hard to understand and maintain.
Code dependencies may be outdated or poorly documented, making it risky to introduce changes without extensive regression testing.
Developers may face challenges refactoring or cleaning up code because small changes can unintentionally affect other parts of the system due to tightly coupled code.
Compliance and Security Risks
Legacy systems may not meet modern security standards, and not support the latest data encryption standards, logging practices, or access control mechanisms.
Security patches for older technologies are less frequent or may no longer be supported, leading to vulnerabilities that can expose financial data to breaches.
Regulatory changes can be challenging to implement in legacy systems that were not designed with modern compliance frameworks in mind, necessitating workarounds or manual processes to stay compliant.
Inflexibility and Scalability Issues
Legacy systems often have a monolithic architecture, where the application is a single codebase with tightly integrated modules. This makes it hard to update specific features without impacting the entire system. This inflexibility can hinder business agility, making it challenging for financial institutions to respond quickly to market demands or adopt new business models.
Scalability is a significant issue, as adding new users or handling higher transaction volumes may strain the system, requiring costly hardware upgrades rather than software optimization. Additionally, integration with modern systems, APIs, or cloud services is difficult due to the rigid structure of older platforms.
TypeScript and Angular bring modern software development practices, a structured approach, and improved performance to the table, addressing the challenges mentioned above. Using these modern tools can significantly streamline the process and deliver more robust, maintainable solutions. Now let’s look at some of the benefits and features provided by Typescript & Angular which ultimately help us in enhancing our ability to innovate in a fast-paced, regulated industry.
Modernizing the Frontend with Angular
Component-Based Architecture: Angular’s structure allows developers to create self-contained, reusable components, making the application easier to maintain and extend. This modular approach makes it easier to incrementally replace parts of the legacy system’s front end. For example, a customer dashboard can be modernized as a standalone Angular component, while the rest of the application remains in the legacy format. This reduces the risk of a complete system rewrite and allows for phased upgrades.
Two-Way Data Binding and Reactive Programming:
Angular’s two-way data binding ensures synchronization between the user interface and the application state, reducing manual data management. Reactive programming features, such as Observables, Subjects etc. help manage asynchronous data flows, which are crucial for real-time financial updates (e.g., stock prices or account balances).
Advanced Templating and Directives:
Angular templates use declarative syntax for binding components and creating dynamic user interfaces. This makes it easier to update and maintaincomplex financial dashboards, trading interfaces, or customer portals.User experience is essential in finance, where users need to view data intuitively and efficiently. Angular’s reactive forms and databinding capabilities enable us to build dynamic UIs that update in real-time, improving the user experience for both internal users and clients.
Leveraging NGRX and RxJS
NGRX and RxJS are powerful tools for managing state and handling asynchronous events in Angular applications, contributing significantly to modernizing the frontend. Our entire codebase heavily relies on usage of RxJS operators, and we have used NGRX in some of the apps where complex state management is required.
Centralized State Management:
NGRX implements the Redux pattern in Angular, offering a centralized store for application state. This means that all state changes flow through a single, predictable path, making it easier to manage and understand complex state flows.
Reactive Data Streams:
RxJS provides a powerful way to handle asynchronous data through Observables, which are especially useful in Angular due to its declarative, component-based structure. Observables allow developers to build non-blocking, event-driven applications that are resilient and responsive.
Handling Complex Async Logic:
In modern applications, data often comes from multiple sources (APIs, user interactions, real-time updates). RxJS operators make it easy to transform, combine, and manage these asynchronous streams in a declarative way, reducing the need for nested callbacks and improving code readability. RxJS also provides robust error handling in streams, making it easy to manage errors and retries in asynchronous operations, which is essential for seamless user experience.
Seamless Integration with NPM packages
NPM packages have greatly helped our team in modernizing the Angular applications by providing a wide range of tools for efficient development, enhanced performance, security, and scalability. They reduce the need for custom code, allow quick adoption of best practices, and enable better collaboration, making it easier to build high-quality, maintainable, and user-friendly applications. Let’s look at some of the key areas where integration with NPM packages has helped our cause.
Access to Community-Created Solutions:
Leveraging pre-built packages for functionality (e.g., authentication, routing, state management, material design components, form validators, and animation libraries etc.) speeds up the development process. Instead of reinventing the wheel, developers can focus on building unique features, reducing time-to-market.
Improving Performance and ensuring security:
Packages that optimize performance, such as lazy loading modules, code splitting, virtual scrolling (e.g., Angular CDK), or image compression libraries, help reduce page load times and memory usage. Also, regular updates, bug fixes, and security patches are available due to community support, ensuring that applications built with these packages stay secure, stable, and compatible with the latest Angular versions.
Maintaining code quality and CI/CD integrations:
Packages like ESLint, Prettier, and TSLint help maintain code quality by enforcing coding standards across the team. By using libraries like Jasmine, Karma, Jest, and Cypress, teams can automate unit, integration, and end-to-end tests, leading to more reliable applications and faster development cycles.
NPM packages for automated builds (like Webpack, Angular CLI) make it easier to adopt modern DevOps practices. These tools automate many steps of development and deployment, ensuring quick, reliable, and repeatable delivery processes. Our team has integrated the CI/CD pipelines with NPM, which allowed us to run tests, linting, and builds as part of every push or pull request, thereby improving the code quality and accelerating the release process.
Architectural Shift from Monoliths to Micro frontends
In the past 2 years, our team has spent a lot of time and effort in transitioning from monolith applications to micro front-end architecture. MFE architecture modernizes an Angular frontend by breaking down a monolithic app into smaller, independently deployable modules. This shift in architecture aligns with modern software principles of modularity, scalability, and team autonomy.
As part of the transition process, we created a new application (Shell UI) which would act as a container/parent app for all the other MFEs. The main responsibility of shell UI is to load the common styles (via common library) for the user journey, and fetch the remote entries (MFE modules) which would be lazily loaded as the user progresses through the app. Shared authentication, UI components, styles and data services were used in micro frontends, ensuring a consistent look and feel while minimizing redundant code. This improved the performance as well as user experience (in app navigation).
These are some of the features of MFE architecture which have largely benefitted our team in modernizing the frontend apps:
Scalability and Modularization:
MFEs allow each part of an Angular application to be developed, deployed, and maintained independently. Each MFE can focus on a specific domain or functionality, enabling better organization and making the app easier to expand.
Independent Deployment:
With MFEs, each module can be deployed independently, this means teams can release updates or fixes to specific parts of the app without waiting for the entire app to be redeployed, speeding up time to market and allowing faster iterations.
Team Autonomy and Parallel Development:
Each micro frontend can be handled by a different team. This division enables parallel development where multiple teams work on distinct features simultaneously without stepping on each other’s toes.
Improved Performance through Lazy Loading:
Micro frontends can be loaded lazily, meaning each module is only loaded when needed. This approach reduces initial load times, as users only download and render the parts of the app relevant to their current interaction, improving performance and user experience.
Isolation for Better Error Handling and Resilience:
Because MFEs are somewhat isolated from each other, errors in one module are less likely to affect others. This separation makes it easier to diagnose issues and enhances the overall resilience of the application.
Leveraging NX Monorepos with Angular
An Nx monorepo modernizes an Angular frontend by introducing a modular, scalable, and efficient development environment. Through optimized CI/CD, shared libraries, best practices enforcement, and enhanced collaboration, Nx transforms the development and maintenance of Angular applications into a more agile, productive, and future-ready process. We have integrated NX with angular and have used NX monorepo architecture for some parts of our application, where these features have greatly helped in improving the application management in I9 ecosystem.
Enhanced Code Sharing and Reusability:
Nx makes it easy to create and manage shared libraries that contain common components, services, or utilities. This reusability benefits large teams that need to maintain consistency across multiple parts of the application, as shared libraries can be updated in one place and automatically consumed by all dependent modules. It reduces duplicated efforts and keeps the codebase maintainable.
Modularization and Scalability:
Nx helps break down an Angular frontend into modular applications and libraries, making it easier to scale and add new features without cluttering the main codebase.
Consistent Development Standards and Best Practices:
Nx offers powerful code generation tools that enforce best practices and code consistency across the project. Nx’s linting, testing, and formatting tools further standardize code quality across teams, reducing errors and boosting productivity.
Optimized CI/CD with Incremental Builds and Tests:
Nx is designed to optimize build and test processes in a monorepo. It can track which parts of the codebase have changed and only rebuild or retest those parts, rather than the entire project. This incremental approach drastically reduces build and test times.
Future-Ready with Angular and Tooling Updates: Nx keeps pace with the latest Angular updates and best practices, so applications built with Nx monorepos can easily adopt new Angular features and improvements. Nx’s continuous updates and toolchain optimizations future-proof applications, allowing them to evolve with the framework.
Angular Upgrades
Regular Angular upgrades help modernize frontend applications by incorporating performance improvements, security patches, new features, better developer tools, and alignment with modern web standards. Our team is aligned with this approach and has performed major incremental upgrades from Angular 8 to Angular 12, and then Angular 12 to Angular 16 in the last 2 years. Here’s a closer look at how regular Angular upgrades contribute to modernizing frontend applications:
Improved Performance and Efficiency:
Each Angular release often includes performance optimizations that make applications faster and more efficient.
Enhanced Security:
Upgrading Angular ensures the app is equipped with the latest security patches and mitigations for vulnerabilities. As older versions may have exposed security flaws, updating to the latest version protects applications against potential attacks.
Alignment with Web Standards and Ecosystem:
Angular upgrades often include updates to ensure compatibility with the latest web standards and tools. This alignment is crucial for staying up to date with JavaScript/TypeScript, RxJS, and other libraries in the ecosystem.
Optimized Dependency Management:
Upgrades often include updates to Angular’s core dependencies (e.g., TypeScript, RxJS), reducing compatibility issues with other libraries and tools.
Enhanced Accessibility and Internationalization:
Angular continually improves support for accessibility and internationalization, allowing developers to build more inclusive applications.
Improved Testing and Debugging:
Angular upgrades often bring improvements to testing frameworks, allowing for faster, more reliable tests and better debugging tools.
Enhancing Code Quality and Safety with TypeScript
Leveraging TypeScript modernizes frontend apps by adding a robust type system, enhancing code quality, improving developer productivity, and making applications more maintainable. TypeScript, as a statically typed superset of JavaScript, offers features that bring consistency, safety, and scalability to complex frontend applications. Our entire codebase is built on TypeScript, and we have made sure to leverage the useful features which are offered by TS to maintain the code quality and build scalable apps.
Static Typing for Better Error Detection:
Finance applications require a high level of precision and robustness. TypeScript’s static type checking catches potential bugs at compile time rather than runtime, which is essential for financial applications where bugs can lead to critical issues such as incorrect calculations or security vulnerabilities.
Enhanced Developer Experience:
TypeScript’s features, like autocompletion, interfaces, and type inference, improve productivity by providing better tooling support. With types, developers get meaningful suggestions and insights into available methods and properties, significantly speeding up development.
Easier Refactoring and Code Maintenance:
With TypeScript, refactoring is safer and more manageable, as the type system helps track where and how different parts of the codebase are used. This is particularly useful for large codebases where small changes can have widespread effects.
Advanced Language Features:
TypeScript introduces modern JavaScript features ahead of time, such as async/await, optional chaining, and nullish coalescing, which make code cleaner and more expressive.
Reduced Testing Effort:
With TypeScript catching errors at compile time, the amount of manual testing needed to catch simple bugs is often reduced.
Scalability and Long-Term Maintainability:
As applications grow and evolve, TypeScript’s strict type-checking ensures that new code integrates seamlessly with existing code, reducing the risks and costs associated with adding new features or restructuring old ones.
To summarize everything mentioned in this blog, we looked at the challenges faced by legacy systems, followed by how the teams can leverage powerful features offered by Angular and TypeScript. By using these features in a strategic manner and depending on the use case, the modernization effort can transform outdated legacy systems into agile, secure, and scalable platforms that meet the needs of the modern financial industry.
Written by
DeepKiran Chantati