Introduction
Managing application state is a critical aspect of JavaScript development, and specialized libraries have emerged to address the complexities of state management. Two prominent contenders in this space are Redux and Mobx.
In this article, we'll dive into the features, concepts, and usage of these libraries to help you make an informed choice for your state management needs.
Suggested Tutorials 📑:
The Need for State Management
As applications grow in complexity, maintaining and sharing state between components becomes challenging. State management libraries offer centralized solutions to streamline this process.
And while there are many state management libraries available, Redux and Mobx are two of the most popular choices for JavaScript applications.
1. Redux
Redux is a predictable state container for JavaScript applications. It enforces a unidirectional data flow pattern and emphasizes immutability to maintain a clear and predictable state management mechanism.
Redux is a popular choice for state management in React applications, but it can be used with any JavaScript framework or library.
1.1 Redux Concepts
Redux is based on three core principles:
- Single Source of Truth: The state of your whole application is stored in an object tree within a single store.
- State is Read-Only: The only way to change the state is to emit an action, an object describing what happened.
- Changes are Made with Pure Functions: To specify how the state tree is transformed by actions, you write pure reducers.
1.1.1 Store
The store is the single source of truth for your application state. It is a JavaScript object that holds the application state and provides a few helper methods to access the state, dispatch actions, and register listeners.
1.1.2 Actions
Actions are payloads of information that send data from your application to the store. They are the only source of information for the store. You send them to the store using store.dispatch().
Actions are plain JavaScript objects. They must have a type property that indicates the type of action being performed. Types should typically be defined as string constants.
1.1.3 Reducers
Reducers specify how the application's state changes in response to actions sent to the store. They are pure functions that take the previous state and an action, and return the next state.
1.1.4 Action Creators
Action creators are functions that create actions. They are useful when you need to pass data to a store's dispatch method.
Suggested Tutorials 📑:
1.1.5 Middleware
Middleware provides a third-party extension point between dispatching an action and the moment it reaches the reducer. It is useful for logging actions, performing asynchronous operations, routing, and more.
1.2 Redux Usage
1.2.1 Installation
To install Redux, run the following command:
npm install redux
1.2.2 Creating a Store
To create a Redux store, you need to provide a reducer to the createStore function:
import { createStore } from 'redux';
const store = createStore(reducer);
1.2.3 Dispatching Actions
To dispatch an action, call the dispatch method on the store object:
store.dispatch({
type: 'ADD_TODO',
payload: 'Learn Redux',
});
1.2.4 Creating Reducers
Reducers are pure functions that take the previous state and an action, and return the next state. They are used to specify how the application's state changes in response to actions sent to the store.
const initialState = {
todos: [],
};
function todoReducer(state = initialState, action) {
switch (action.type) {
case 'ADD_TODO':
return {
...state,
todos: [...state.todos, action.payload],
};
default:
return state;
}
}
Suggested Tutorials 📑:
1.2.5 Combining Reducers
Redux provides a combineReducers helper function to combine multiple reducers into a single reducer function:
import { combineReducers } from 'redux';
const rootReducer = combineReducers({
todos: todoReducer,
visibilityFilter: visibilityFilterReducer,
});
1.2.6 Subscribing to Store Changes
You can subscribe to store changes using the subscribe method:
store.subscribe(() => {
console.log(store.getState()); // { todos: ['Learn Redux'] }
});
2. Mobx
Mobx is a simple, scalable, and battle-tested state management solution. It is based on the observable state tree concept, which allows you to create observable objects and derive computed values from them.
Mobx is a popular choice for state management in React applications, but it can be used with any JavaScript framework or library.
2.1 Mobx Concepts
Mobx is based on three core principles:
- Observable State: The state of your application is stored in an observable state tree.
- Derivations: Derivations are computed values that are derived from the state tree.
- Reactions: Reactions are side effects that are automatically triggered when the state tree changes.
2.1.1 Observable State
Mobx uses observable state trees to store the state of your application. Observable state trees are plain JavaScript objects that can be observed for changes.
Suggested Tutorials 📑:
2.1.2 Derivations
Derivations are computed values that are derived from the state tree. They are automatically updated when the state tree changes.
2.1.3 Reactions
Reactions are side effects that are automatically triggered when the state tree changes. They are useful for logging, updating the UI, and more.
2.2 Mobx Usage
2.2.1 Installation
To install Mobx, run the following command:
npm install mobx
2.2.2 Creating Observable State
To create an observable state tree, use the observable function:
import { observable } from 'mobx';
const todoStore = observable({
todos: [],
});
2.2.3 Creating Derivations
To create a derivation, use the computed function:
import { observable, computed } from 'mobx';
const todoStore = observable({
todos: [],
get todoCount() {
return this.todos.length;
},
});
Suggested Tutorials 📑:
2.2.4 Creating Reactions
To create a reaction, use the reaction function:
import { observable, reaction } from 'mobx';
const todoStore = observable({
todos: [],
});
reaction(
() => todoStore.todos.length,
(length) => console.log(length)
);
Conclusion
Redux and Mobx are both excellent choices for state management in JavaScript applications. They both offer unique features and concepts that can help you streamline your state management needs.
In this article, we explored the features, concepts, and usage of these libraries to help you make an informed choice for your state management needs.
We hope you found this article useful.
Happy coding! 🎉