react之相关组件API

学习参考资料;菜鸟教程；

react入门教程实例-阮一峰；

一.无状态组件：没有生命周期，没有数据传递，只是用于view层显示；

import React,{Component} from "react"; // 引入react库文件

// 创建组件
export default ()=>{
  return(
        <div>
            我是无状态组件！
        </div> 
    )


}

上面只是创建组件，如何引入组件是非常简单的，想要知道，可以在上一节（react数据传递那块）去了解这个组件的完整的创建过程；

ReactDOM.render 是 React 的最基本方法，用于将模板转为 HTML 语言，并插入指定的 DOM 节点；

引用于：http://www.ruanyifeng.com/blog/2015/03/react.html；（react入门教程实列）

正因为这个，我们组件的内外部的引入；

class Index extends Component{//创建内部组件
  
  render(){
    
    return(
            <div>
               
               <Nostate></Nostate>{//外部组件引入；

               }

            </div>
    )
  }
}

ReactDOM.render(<div>
  我是谁的人！
  <Index />{
    //内部组件引入；
  }
  </div>,document.getElementById("root"))

组件的引包省略；

react不存在双向数据绑定：可以模拟双向数据绑定；通过event.target方法去改变；

this.state={
    
          txt:""
    
       
  }
render(){
   
    return(
      <div> 
        
            <input type="text"  onChange={this.chang.bind(this)} />
            {this.state.txt}
      </div>
    )

     }
chang(event){
 this.setState({txt:event.target.value})
}

接下来要讲一下，关于propTypes的这个东西；

引入：

cnpm install prop-types --save
import PropTypes from 'prop-types'
就是类型检测，检查代码bug

import PropTypes from 'prop-types';

MyComponent.propTypes = {
  // You can declare that a prop is a specific JS primitive. By default, these
  // are all optional.
  optionalArray: PropTypes.array,
  optionalBool: PropTypes.bool,
  optionalFunc: PropTypes.func,
  optionalNumber: PropTypes.number,
  optionalObject: PropTypes.object,
  optionalString: PropTypes.string,
  optionalSymbol: PropTypes.symbol,

  // Anything that can be rendered: numbers, strings, elements or an array
  // (or fragment) containing these types.
  optionalNode: PropTypes.node,

  // A React element.
  optionalElement: PropTypes.element,

  // You can also declare that a prop is an instance of a class. This uses
  // JS's instanceof operator.
  optionalMessage: PropTypes.instanceOf(Message),

  // You can ensure that your prop is limited to specific values by treating
  // it as an enum.
  optionalEnum: PropTypes.oneOf(['News', 'Photos']),

  // An object that could be one of many types
  optionalUnion: PropTypes.oneOfType([
    PropTypes.string,
    PropTypes.number,
    PropTypes.instanceOf(Message)
  ]),

  // An array of a certain type
  optionalArrayOf: PropTypes.arrayOf(PropTypes.number),

  // An object with property values of a certain type
  optionalObjectOf: PropTypes.objectOf(PropTypes.number),

  // An object taking on a particular shape
  optionalObjectWithShape: PropTypes.shape({
    color: PropTypes.string,
    fontSize: PropTypes.number
  }),

  // You can chain any of the above with `isRequired` to make sure a warning
  // is shown if the prop isn't provided.
  requiredFunc: PropTypes.func.isRequired,

  // A value of any data type
  requiredAny: PropTypes.any.isRequired,

  // You can also specify a custom validator. It should return an Error
  // object if the validation fails. Don't `console.warn` or throw, as this
  // won't work inside `oneOfType`.
  customProp: function(props, propName, componentName) {
    if (!/matchme/.test(props[propName])) {
      return new Error(
        'Invalid prop `' + propName + '` supplied to' +
        ' `' + componentName + '`. Validation failed.'
      );
    }
  },

  // You can also supply a custom validator to `arrayOf` and `objectOf`.
  // It should return an Error object if the validation fails. The validator
  // will be called for each key in the array or object. The first two
  // arguments of the validator are the array or object itself, and the
  // current item's key.
  customArrayProp: PropTypes.arrayOf(function(propValue, key, componentName, location, propFullName) {
    if (!/matchme/.test(propValue[key])) {
      return new Error(
        'Invalid prop `' + propFullName + '` supplied to' +
        ' `' + componentName + '`. Validation failed.'
      );
    }
  })
};

其他API之classnames:

这个API是通过给组件和组件内部进行定义类名；如何进行定义呢，接下来我为大家介绍一下，废话不多说啦，先要安装classnames

npm install --save-dev classnames

classnames就像封装好的一个模块进行将类名进行引入，非常方便好用，当然内部也可以自定义类名，不会对其进行修改，只会往后叠加而已，在需要的组件内部进行引包；

import ClassNames from 'classnames'

然后进行自定义：

const classes = ClassNames('love job who',props.className)

<div className={classes}/>

这样就完成了内部定义classnames值啦。

react之相关组件API

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