Top Angular State Management Solutions for Web Applications

Managing web application state effectively is crucial for mid-sized to enterprise Angular applications to ensure performance, consistency, and a seamless user experience. Here we explore the different types of app state management solutions and libraries available in 2024.

App state refers to the data that dictates the behavior and display of a web app at any given time. This data can include user inputs, responses from server APIs, or UI component states (like whether a menu is open or closed). Proper state management helps keep components synchronized, share data across the app, and manage user interactions and API calls efficiently. Without adequate state management, maintaining and debugging complex applications becomes increasingly challenging, leading to performance issues, making code less clean and prone to errors.

In 2017, Victor Savkin wrote a brilliant article about app states, where he classifies them into several categories:

• Server State

  This state is stored on the server side, typically in a database, and fetched via, for example, a REST endpoint.

• Persistent State (Client Cache)

  This includes server data cached on the client side to minimize server requests and improve performance. Cached data such as user settings or search results is stored locally, ensuring quicker access and reducing server load. This state should be synchronized with server state to maintain consistency across sessions and users.

• Navigation, Router State

  Managed by Angular's Router, this state includes the current route URL, query parameters, and route-specific data. It allows users to bookmark specific states of the application and use browser navigation buttons effectively.

• Client and Session State

  This state persists throughout a user session, often containing authentication tokens and user preferences. It is crucial for providing a personalized experience without needing to re-login on each navigation.

• Local UI State

  This state is managed internally by components, such as form inputs or button visibility. It is typically short-lived and only relevant within the scope of individual components, making it ideal for simple, isolated interactions.

RxJS (Reactive Extensions for JavaScript) is a library that enables reactive programming using the Observable pattern, making it easier to handle asynchronous data streams and events.

In Angular, RxJS is a fundamental tool for managing asynchronous operations, like HTTP requests and event handling. Modern Angular state management mostly involves Redux-based solutions built with RxJS, with a Store serving as the single source of truth, and other components like Actions and Selectors helping maintain a read-only Store state and unidirectional data flow, enhancing consistency in applications.

Given these fundamental concepts, there are multiple solutions available for managing state in Angular applications, each tailored to different types of managed state and levels of app complexity. Below is a comprehensive list of such state management solutions.

State Management Solutions

• Service with a Subject

  This approach requires manual implementation, it uses Angular services to manage state across components. It is implemented using Angular’s built-in dependency injection system to inject a singleton service to share state among components. Other components get data by accessing a property of the service that is implemented either as an ordinary basic type, or a Subject that holds a value — a reactive push-based approach. This method is straightforward and effective for small-scale applications.

• NgRx Component Store

  An alternative to the "Service with a Subject" approach, this standalone library helps manage component-specific state using NgRx patterns. It is suitable for handling complex component-specific states and does not have native persistence support.

• Angular Signals

  Introduced in Angular v16 (2023), this provides a reactive programming model using the Signals API for managing component-level states. It is suitable for medium complexity scenarios but does not offer built-in state persistence.

• NgRx Signals

  Released in 2023, this lightweight library leverages Angular Signals for state management. It provides a reactive state management solution that integrates seamlessly into the NgRx ecosystem, making it suitable for scalable projects. It supports computed signals, state tracking, and integrates with NgRx’s libraries for state persistence and debugging.

• NgRx Store

  The most popular and comprehensive state management solution for Angular based on the Redux pattern. It’s ideal for large, complex applications, offering actions, reducers, and memoized selectors to manage global, application-wide state. Supports persistence through the @ngrx-store-localstorage package and debugging via the @ngrx/store-devtools package and Chrome's Redux DevTools extension.

• NGXS

  A community-built state management library that reduces boilerplate and simplifies state management using modern TypeScript features like decorators. It includes built-in state persistence capabilities through the @ngxs/storage-plugin package, making it suitable for moderate to complex applications.

• Elf

  Released in 2023, a reactive state management solution, focusing on simplicity and scalability. Based on RxJS, Elf offers a modular, customizable approach, supporting immutability, entity management, and state persistence. Elf's lightweight API makes it easy to integrate and use. It integrates with the Redux DevTools Chrome extension.

Summary

Choosing the right state management solution depends on your application’s complexity and scalability needs.

When developing SaaS web applications for our clients, our company recommends using solutions from the NgRx ecosystem, such as NgRx Store and NgRx Signals. These libraries offer comprehensive tooling support and strong community backing. Additionally, they ensure consistent and maintainable code architecture, facilitate easier testing, and integrate seamlessly with Angular’s ecosystem.

While they introduce some complexity due to relying on RxJS, the benefits in scalability, maintainability, and developer productivity make them a preferred choice for modern Angular applications.