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import ReactDOM ,{c} from 'react-dom';
//{c}是属性, 相当于xxx.c
const { name, age } = props; //ES6 //解构是对象的选择赋值
理解:export
第一个
import React from 'react';
import ReactDOM from 'react-dom';
const Headline = () => {
return <h1>Welcome to React world.</h1>;
}
const Greeting = (props) => {
return <p>You will love it {props.name} ({props.age})!</p>;
}
export const App = () => {
return (
<div>
<Headline />
<Greeting name="John" age={25} />
</div>
)
}
var mount = document.querySelector('#root');
ReactDOM.render(<App />, mount);
第二个 使用解构 const { name, age } = props; //ES6
import React from 'react';
import ReactDOM ,{c} from 'react-dom';
//{c}是属性, 相当于xxx.c
const Headline = () => {
return <h1>Welcome to React world.</h1>;
}
const Greeting = (props) => {
const { name, age } = props; //ES6 //解构是对象的选择赋值
return <p>You will love it {name} ({age})!</p>;
}
export const App = () => {
return (
<div>
<Headline />
<Greeting name="John" age={25} />
</div>
)
}
var mount = document.querySelector('#root');
ReactDOM.render(<App />, mount);
第三个类型检查
建立一个
import React from "react";
import ReactDOM from "react-dom";
import PropTypes from "prop-types";
const Headline = () => {
return <h1>Welcome to React world.</h1>;
};
const Greeting = props => {
const { name, age } = props; //ES6
console.log();
return (
<p>
You will love it {name} ({age})!
</p>
);
};
export const App = () => {
return (
<div>
<Headline />
<Greeting name="John" age={25} />
</div>
);
};
Greeting.propTypes = {
name: PropTypes.string,
age: PropTypes.number.isRequired
};
var mount = document.querySelector("#root");
ReactDOM.render(<App />, mount);