第 4:13 行：'React' 未定义 no-undef

Question

When i want to create an element without JSX it shows me this error 'React' is not defined no-undef . I am a beginner. I don't know what is the problem. Can anyone help

import logo from './logo.svg';
import './App.css';

const app = React.createElement("h1", null, "Without JSX");  // Showing an error

function App() {
  return (
    <div className="App">
      {app};
    </div>
  );
}

export default App;

These messages are shown in VS code Terminal.

Failed to compile.

./src/index.js
SyntaxError: E:\react_js_course\src\index.js: Unexpected token, expected "," (11:2)
Failed to compile.

src\App.js
  Line 4:13:  'React' is not defined  no-undef

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Answer 1

A couple points just based on the code you provided:

1. You are using JSX in your example: your App component returns JSX, so React should be in scope to do that.

2. You are explicitly using the React method createElement so React should be available in this file .

To fix both issues add import React from 'react'; at the top of this file.

Answer 2

import React from 'react' is required for writing code in JSX and alternative you use ES7 snippet which help to auto populate the code

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