¶ Redux
¶ SDK Libraries
Introduction to Redux: Understanding the Heartbeat of Modern State Management
Every developer, at one point or another, comes face-to-face with the quiet chaos of application state. You might start with a simple idea—a button that toggles something, a list that updates, a form that collects information. It all feels manageable in the beginning. But as your application grows, as components multiply, as interactions become more intertwined, you begin to feel that pull: things start slipping through the cracks. State becomes harder to track. Logic gets scattered across components. Updates happen when you least expect them. Something in your code, somewhere, is deciding to act on its own.
This is the moment when Redux begins to matter.
Redux has earned its place in the modern developer’s toolkit not because it’s trendy, not because everyone else uses it, but because it addresses a fundamental struggle in application development: the need for predictable, centralized state. At its core, Redux is a pattern—an elegant, surprisingly compact idea about how data should flow through an application. But more importantly, Redux is a mindset. Learning Redux is less about learning functions and more about learning how to think about state with clarity.
This course, spanning one hundred articles, is designed to immerse you in that mindset. But before you begin that journey, it’s worth understanding why Redux exists, what problems it was born to solve, and why it continues to matter in a world where new state management tools appear almost every month.
If you’ve ever built a medium-to-large application without a predictable state layer, you know how quickly things get messy. State becomes scattered across components. Logic gets duplicated. A simple UI change ripples through the system in ways you didn’t anticipate. Debugging becomes a hunt through layers of props, hooks, and side effects. And worst of all, the application starts behaving in ways you can’t fully explain.
Redux emerged as a response to that pain—a way to centralize state so that you always know where it lives, where it’s going, and how it changes. Its core principles are disarmingly simple: keep one source of truth, make state read-only, and describe every change with pure functions. That’s it. Yet those ideas, when combined, create an architecture that feels stable, clean, and deeply logical.
When developers describe Redux, they often talk about predictability. And it’s true—the predictability is almost addictive. Every state change is documented. Every action is explicit. Every update flows through the same predictable path. Debugging becomes less about hunting and more about understanding. You can replay sequences of actions, inspect state transitions, travel backward in time, and see precisely how your application reached its current state. In a world where apps can feel like swirling storms of components, side effects, and asynchronous calls, Redux feels like a calm center.
But describing Redux this way can make it sound like a dry, strictly logical system—something rigid, something academic. In reality, Redux has an almost organic feel when you work with it. It gives shape and rhythm to your data. It encourages you to think in terms of events and consequences. It lets you express your application’s behavior as a simple narrative: something happens, the system reacts, and the state updates. It’s a story your code tells—one that becomes easier to read the more you embrace the principles behind it.
This course will help you learn that story well. Over time, you’ll understand not just the “how” but the “why” behind Redux—why actions exist, why reducers are pure, why middlewares matter, and why a unidirectional data flow leads to applications that feel stable even as they grow in complexity.
One of the reasons Redux spread so quickly through the JavaScript ecosystem—and why it remains relevant today—is that it solves a universal problem. It doesn’t matter whether you’re building a web app, a mobile app, a desktop app, a game UI, or even a server-side system. State is everywhere. And wherever state exists, the potential for confusion exists too. Redux gives you a way to tame that confusion.
It also helps that Redux is incredibly flexible. It doesn’t care what UI library you use. It doesn’t force you into a specific architecture. It doesn’t dictate how you organize your code. It simply provides a structured way to manage state and a set of tools to help you work with that structure. You can pair Redux with React, Vue, Svelte, Angular, plain JavaScript, or any rendering system you choose. The library has found its home most prominently in React, but its principles are universal.
But as much as Redux is loved, it’s also misunderstood. Many developers assume it’s complex because they’ve seen codebases with sprawling reducers, endless boilerplate, and tangled action types. The truth is that Redux itself is incredibly small. The heart of Redux is just a handful of functions. The complexity often arises from patterns and tooling layered on top of it. This course will strip away that noise. You’ll learn how Redux actually works—how actions flow, how the store updates, how middleware extends the architecture, how asynchronous operations fit into the system, and how modern Redux tooling simplifies everything dramatically.
Modern Redux, particularly with Redux Toolkit, has grown far simpler and more pleasant than many people realize. Gone are the days when you needed to write dozens of files for the smallest state update. Today, Redux encourages concise, expressive patterns that make state management feel almost effortless. It retains all the clarity and predictability that made it special, but without the overhead that once intimidated newcomers.
This course will follow the evolution of Redux from its fundamental ideas to its modern best practices. You’ll see how the library has matured, how the community has shaped it, and how it integrates seamlessly with modern development workflows. You’ll understand the difference between Redux concepts and Redux tooling. You’ll learn when Redux is the right choice—and when it isn’t. Because as important as Redux is, it’s not a hammer for every nail, and part of becoming fluent in state management is knowing how to choose your tools wisely.
But before diving into all of that, it’s worth appreciating Redux on a more philosophical level. Redux encourages a way of thinking that many developers find transformative. It pushes you to design your application around clear events and reactions. It gives you a language to describe change. It forces you to separate pure logic from side effects. These ideas aren’t limited to Redux—they’re foundational to good software design. Many developers who learn Redux well find themselves writing cleaner code in every other part of their stack.
This is why Redux has lasted. Libraries come and go. New patterns appear constantly. But the fundamental concepts behind Redux—immutability, explicitness, predictable data flow—remain valuable no matter what framework you’re using. They reflect deeper truths about managing complexity. They reflect the need for systems that behave the same way today, tomorrow, and a year from now. They reflect the idea that every change in an application should be understandable, inspectable, and intentional.
This course embraces that deeper perspective. Yes, you’ll learn the APIs, the tools, the patterns, the best practices. But you’ll also learn a way of thinking about applications that transcends Redux itself. You’ll learn how to see state not as a scattered mess of variables, but as a coherent story. You’ll learn how to architect systems that remain stable even as your feature set grows. You’ll learn how to create applications that feel easier to read, easier to reason about, and easier to maintain.
The next hundred articles will take you on that journey. You’ll begin with the fundamentals, then explore the internals, then step into practical scenarios, advanced patterns, ecosystem libraries, performance considerations, testing strategies, and real-world architectural decisions. But it all starts here—with an understanding of why Redux exists and why developers continue to rely on it.
So as you step into this course, leave behind any preconceptions you may have heard—whether they’re glowing praise or harsh criticism. Redux is neither a magic solution nor an outdated relic. It is a thoughtful, well-designed state management system that continues to evolve, adapt, and empower developers across the world.
You’re about to learn how it really works. More importantly, you’re about to learn how to harness its strengths to build applications with clarity, confidence, and elegance.
Welcome to the beginning of the journey. Here, your understanding of state management will deepen. Your intuition will grow. And by the end of these hundred articles, Redux will feel not like a tool you use, but a language you speak.
¶ Redux
¶ Part 1: Introduction to Redux
1. What is Redux? An Introduction to State Management
2. Why Redux? Solving Complex State Management Problems
3. The Core Concepts of Redux: Store, Actions, and Reducers
4. Setting Up Redux: Installation and Basic Setup
5. Understanding the Redux Flow: From Actions to Store
6. First Redux Application: Managing State in a Simple App
7. Exploring Redux DevTools for Efficient Debugging
8. Understanding the Redux Store: A Single Source of Truth
9. Actions: Defining and Dispatching Actions in Redux
10. Reducers: Managing State with Pure Functions
¶ Part 2: Core Concepts of Redux
11. The Role of Middleware in Redux
12. Understanding Redux Thunk: Handling Asynchronous Logic
13. Dispatching Actions: How State Changes in Redux
14. Handling Synchronous vs Asynchronous Actions in Redux
15. Understanding Reducers: Combining Multiple Reducers
16. Understanding the Immutable Nature of Redux State
17. The Power of Redux with Multiple Reducers and Combined State
18. Breaking Down the Flow: From Action to Reducer to View
19. The Role of the Redux Store in Modern JavaScript Apps
20. Understanding Redux’s Unidirectional Data Flow
¶ Part 3: Advanced Redux Concepts
21. Handling Complex State with Redux: Nested Objects and Arrays
22. Redux Middleware: Understanding the Role of Custom Middleware
23. Redux Toolkit: Simplifying Redux Development
24. Action Creators: Automating Action Dispatching
25. Reducers in Depth: Advanced Patterns and Strategies
26. Handling Errors in Redux: Error Boundaries and Action Types
27. Understanding Redux DevTools: Monitoring and Debugging State Changes
28. Using Redux in a Large Application: Best Practices
29. Efficient State Updates in Redux: Avoiding Unnecessary Renders
30. Memoization in Redux: Preventing Redundant Computations
¶ Part 4: Redux Patterns and Best Practices
31. Normalized State in Redux: Benefits and Strategies
32. Using Redux for Local State: Is Redux Overkill?
33. Avoiding Anti-Patterns in Redux
34. Handling Non-UI Data in Redux
35. Choosing Between Local Component State and Redux
36. Code Splitting and Lazy Loading with Redux
37. Modularizing Redux with Feature-Based Folder Structures
38. Managing Multiple Async Operations in Redux
39. Action Payloads: Structuring Data for Efficient State Updates
40. Best Practices for Handling Nested Arrays and Objects in Redux
¶ Part 5: Redux Middleware and Side Effects
41. The Role of Middleware in Redux
42. Using Redux Thunk for Handling Async Actions
43. Introduction to Redux-Saga: Managing Side Effects with Generators
44. Advanced Redux-Saga Patterns
45. Using Redux-Observable for Reactive Programming
46. Custom Middleware: Intercepting Actions and State Updates
47. Debugging Redux Middleware: Troubleshooting Common Issues
48. Integrating with External APIs: Async Logic with Redux
49. Handling Authentication Flow in Redux
50. Throttling and Debouncing Actions in Redux
¶ Part 6: Integrating Redux with React
51. Integrating Redux with React: React-Redux Library Overview
52. Using connect() to Link Redux with React Components
53. Mapping State and Dispatch to Props
54. Introduction to Redux Hooks: useDispatch and useSelector
55. Handling Local State with Redux and React
56. Optimizing React and Redux Performance
57. Using Redux for Global State in React
58. React Context vs Redux: When to Use What
59. Using React-Redux’s Provider for State Management
60. Connecting Redux to Functional Components in React
¶ Part 7: Advanced Redux with React
61. Handling Form State with Redux
62. Handling Dynamic Forms with Redux Form
63. Using Redux for Server-Side Rendering (SSR) with React
64. Redux for Large-Scale Applications with React
65. Optimizing React-Redux Performance with Reselect
66. Code-Splitting and Lazy Loading Redux-Connected Components
67. Advanced Component-Redux Patterns in React
68. Using Redux DevTools with React
69. Testing React-Redux Applications
70. Code Sharing between Redux and React Components
¶ Part 8: Debugging and Testing Redux Applications
71. Using Redux DevTools to Debug State Changes
72. Unit Testing Redux Reducers and Action Creators
73. Mocking Redux State for Component Testing
74. Testing Redux Thunk and Async Actions
75. Test-Driven Development with Redux: Strategy and Tools
76. Integration Testing Redux and React
77. Handling Errors in Redux: Testing Error States
78. Using Jest for Redux Testing
79. Test-Driven Development with Redux-Saga
80. Debugging Redux with Logging and Error Boundaries
¶ Part 9: Performance Optimization in Redux
81. Optimizing Redux State Updates with Pure Components
82. Avoiding Unnecessary Renders in React-Redux
83. Using Reselect for Memoizing Computed Data
84. Performance Tuning Redux Middleware
85. Optimizing Async Actions in Redux
86. Efficient Data Fetching with Redux
87. Reducing the Size of Redux State for Better Performance
88. Redux-Persist: Persisting Redux State Across Sessions
89. Handling Large Data Sets with Redux
90. Optimizing Redux for Mobile Applications
¶ Part 10: Real-World Redux Use Cases
91. State Management in a Large E-Commerce Application
92. Building a Chat Application with Redux
93. Managing Authentication and Authorization with Redux
94. Building a Dashboard with Redux and React
95. Real-Time Data with WebSockets and Redux
96. Using Redux to Manage Global Settings in a Web App
97. Building a Multi-Step Form with Redux
98. Using Redux for Managing Complex UI States
99. Integrating Redux with Firebase or other Real-Time Databases
100. Building a Progressive Web App (PWA) with Redux