What are the differences between Redux and MobX?

Main differences:

• Philosophy: Redux uses an immutable state paradigm and a unidirectional data flow. MobX employs reactivity and mutable state paradigms.
• State storage: In Redux, the state is stored in a single centralized store object. In MobX, the state can be distributed across multiple observables.
• State update: In Redux, the state is updated through actions processed by reducers that return a new state. In MobX, the state is updated directly by mutating observables.
• Change tracking: Redux uses selectors to pick data from the state. MobX automatically tracks dependencies between observables and reactively updates components when data changes.
• Boilerplate: Redux often requires more boilerplate code due to the need to write actions, reducers, constants, and selectors. MobX, thanks to its reactive nature, can be more concise.
• Performance: In some scenarios, MobX can be faster due to more granular dependency tracking and the absence of deep object comparisons during state updates, as is common in Redux with immutable state. However, Redux with proper optimization (e.g., reselect) can also achieve high performance.

Difference	Redux	MobX
Philosophy	Immutable state, Unidirectional flow	Reactivity, Mutable state
State storage	Single central store	Distributed observables
State update	Through actions and reducers	Direct mutation of observables
Change tracking	Selectors	Automatic dependency tracking
Boilerplate	More	Less
Performance	May require optimization	Often faster in simple cases

// Example of update in Redux
// action creator
const setUserName = (name) => ({
  type: 'SET_USER_NAME',
  payload: name,
});

// reducer
const userReducer = (state = { name: '' }, action) => {
  switch (action.type) {
    case 'SET_USER_NAME':
      return {
        ...state, // Create a new state object
        name: action.payload,
      };
    default:
      return state;
  }
};

// Example of update in MobX
import { observable, action } from 'mobx';

class UserStore {
  @observable name = ''; // Observable property

  @action // Action that changes state
  setUserName(name) {
    this.name = name; // Direct mutation
  }
}

Choosing between Redux and MobX depends on project requirements, team preferences, and complexity of state management. Redux is often preferred for large, complex applications where predictability and debugging are important. MobX can be more convenient for small to medium projects where a faster start and less code are desired.