1. Where does it come from?

State is a core concept in React applications, used to control the behavior and rendering of components.

• Origin: React's design philosophy is reactive and declarative, where the concept of state provides a dynamic data source for components.
• Comparison: Before React, traditional JavaScript DOM manipulation was mostly imperative, involving direct DOM manipulation to change the interface. React introduced the concept of state as a more efficient way to control interface updates.

2. What is it?

In React, the state is an object that stores data affecting the rendering and behavior of a component.

• Method of Solution: State allows components to update themselves based on changes in user interaction or other factors.
• Three Key Principles:
  1. State should be as simple as possible to avoid unnecessary complexity.
  2. State updates may be asynchronous, so new state should not rely on the current state value.
  3. State should be limited to data that affects rendering, avoiding storing unrelated data in the state.

Example:

Background

Suppose there is a numeric counter component that needs to display and update a number count.

Application

Use state to store the count value, and update the state to increase the count when a button is clicked.

Code Example

class Counter extends React.Component {
    constructor(props) {
        super(props);
        this.state = { count: 0 };
    }

    incrementCount = () => {
        this.setState(prevState => ({
            count: prevState.count + 1
        }));
    };

    render() {
        return (
            <div>
                <p>{this.state.count}</p>
                <button onClick={this.incrementCount}>Increment</button>
            </div>
        );
    }
}
                

3. Where is it going?

• Limitations: Improper management of state can lead to components being difficult to maintain, especially in large projects.
• Direction for Optimization: Use state management libraries (like Redux, MobX) or the Context API for better state sharing between components.
• Future Development: Future versions of React may introduce more tools and methods to simplify state management, enhancing the performance and maintainability of applications.