react = Virtual DOM + component + data flow + jsx
核心是Virtual DOM结构的状态维护、渲染机制及UI系统的DOM组织功能；
基于Virtual DOM的视图构建和渲染方式。
入口为index.html；
一、虚拟DOM
基于状态管理的UI组件化技术
at its core it’s made up of functional components, with clear direction on how to manage state properly.
- Frequent DOM manipulations are expensive and performance heavy.
- Virtual DOM is a virtual representation of the real DOM.
- When state changes occur, the virtual DOM is updated and the previous and current version of virtual DOM is compared. This is called “diffing”.
- The virtual DOM then sends a batch update to the real DOM to update the UI.
- React uses virtual DOM to enhance its performance.
- It uses the observable to detect state and prop changes.
- React uses an efficient diff algorithm to compare the versions of virtual DOM.
- It then makes sure that batched updates are sent to the real DOM for repainting or re-rendering of the UI.
https://www.cnblogs.com/feng9exe/p/11084600.html
二、component
status/propts
生命周期管理；
状态管理；
渲染：
const element = <h1>Hello, world</h1>;
.(,.());
事件；
三、jsx
React发明了JSX，利用HTML语法来创建虚拟DOM。
当遇到<，JSX就当HTML解析，遇到{就当JavaScript解析。
render() {
return React.createElement(
"div",
null,
"Hello ",
this.props.name
);
}
render() {
return (
<div>
Hello {this.props.name}
</div>
);
}
四、架构模式—MVC模式
While React is the ‘V’ in the MVC structure, Flux fills in the ‘M’ and ‘C’ components.
ReactJS In the simple and popular term, React is the V (View) in MVC (Model/View/Controller).
五、数据流
- When state changes occur, the virtual DOM is updated and the previous and current version of virtual DOM is compared. This is called “diffing”.
- The virtual DOM then sends a batch update to the real DOM to update the UI.
- Last but not the least, React utilizes unidirectional data flow, ensuring a clean data flow architecture throughout your application. This focused flow allows developers to have a better control over the functions.
六、依赖库管理
package
node install x