React兩個bug踩坑

ReactDOM

import React from 'react';
import App from './App';

React.ReactDOM.render(<App />, document.getElementById('root'));
複製程式碼

console報錯render找不到，這是因為react已經把ReactDOM分離出來，這樣引用會出錯，改為

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

ReactDOM.render(<App />, document.getElementById('root'));
複製程式碼

後正常

return 錯誤

console錯誤資訊

Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null
複製程式碼

這是因為程式碼中return同一行沒有程式碼

render(){
    return 
    (
      <div>
        <p>App test</p>
      </div>)
  }
複製程式碼

改為

render(){
    return (
      <div>
        <p>App test</p>
      </div>)
  }
複製程式碼

後正常