Redux is a state management library that can be used as a data store for any UI side of web applications. Its most common use is in React and React Native applications. Redux provides a subscription service that can be used by React components to synchronize the state. It also implements a centralized state which can be synchronized between React components without requiring a parent/child relationship.
What is State?
The state is a built-in react object that is used to hold data or information about a component and control its behavior. A component’s state can change over time in response to user actions or system events. Whenever the state of the component is changed, the component will re-render itself with the updated state.
React applications are built using components, each of which manages its own state. This works well for applications with few components, but as the number of components grows, managing state across shared components becomes more complex.
How State Management Solves the Problem?
Redux helps keep our application organized by centralizing our data in one store. This store is the “single source of truth” for our components, meaning we can rely on it to have the most accurate data at any given time. This helps reduce the need to manually sync data between components, making our application simpler and more efficient.
Principles of Redux
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Single Source of Truth
The state of your entire application is stored in an object within a single store. This makes debugging easy and development faster
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State is Read-only
If you want to change the state of your application, you must emit an action. An action is an object that describes what happened. This means without dispatching an action, we cannot change the state directly
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Changes are made with Pure Functions
In order to specify how the state is transformed by actions, you need to write pure reducers. A reducer is a function where state modification takes place; state and action as arguments and returns a newly updated state
Redux is Composed of the following Components
Action
Redux actions are JavaScript objects that contain the information needed to update the store. The type of action and the payload are both present within the action. Actions are the only things that can trigger a change in the store.
Reducer
In Redux, a reducer is a function that provides a new state based on action and the previous state of the application. The reducer takes two parameters, state, and action. The state is the most recent state of the application, and the action is the new action that has occurred. The reducer uses a switch statement to determine which type of action it is dealing with and updates the state. If there is an unknown action, it should return the state so that the application doesn’t lose its current state.
Store
A store contains the entire state tree of your application. The only way to change the state inside it is to dispatch an action on it.
Data Flow
Redux is a powerful tool and a great choice for managing state in React applications, especially when your applications grow larger and have more components. It follows the unidirectional data flow, which means all the data in an application follows the same lifecycle pattern. Although Redux can be easily integrated into any project, you should only implement Redux if you determine your project needs a state management tool.
