'React' refers to a UMD global, but the current file is a module

Question

I updated my project to create react app 4.0, and I'm slowing moving over my files to TypeScript. I know with this new version you don't have to repetitively import React from 'react'. However, within all of my TS files where I'm not importing React I receive this error 'React' refers to a UMD global, but the current file is a module. Consider adding an import instead.ts(2686). I know I can fix it by importing React, but I thought this was no longer needed. Also, could someone explain the meaning of this error?

My basic TSX file

const Users = () => {     return <>Teachers aka Users</>; };  export default Users; 

Answer 1

Create React App supports the new JSX transformation out of the box in version 4 but if you are using a custom setup, the following is needed to remove the TypeScript error when writing jsx without import React from 'react':

• typescript version of at least version 4.1
• react and react-dom of at least version 17
• tsconfig.json must have a jsx compilerOption of react-jsx or react-jsxdev

example:

// tsconfig.json {   "compilerOptions": {     ...     "jsx": "react-jsx"     ...   }, } 

TypeScript documentation for its support of React 17 JSX Factories can be found here

Answer 2

This error message comes from TypeScript compiler. The React 17 new jsx transform is not currently supported in Typescript 4.0, and will be supported in 4.1.

TypeScript v4.1 Beta - React 17 JSX Factories