Module './App' was resolved to '/Users/leandro/www/helps/web/src/App.tsx', but '--jsx' is not set. code example

Example: Cannot use JSX unless the '--jsx' flag is provided.

// Well I worked around it by adding 
 "jsx": "react" 
// to tsconfig.json, as far as I can tell,
// but that is missing the point.

// When you open a TSX file (not a directory), 
// you don't have a tsconfig.json file.