JSX not allowed in files with extension '.tsx'eslint(react/jsx-filename-extension)

You probably want to configure the react/jsx-filename-extension rule in your .eslintrc.js so that ESLint is happy about JSX inside your TypeScript files:

rules:  {
  'react/jsx-filename-extension': [2, { 'extensions': ['.js', '.jsx', '.ts', '.tsx'] }],
},

Add this rule under the rules section of your eslint configuration:

"rules": {
  "react/jsx-filename-extension": [1, { "extensions": [".tsx", ".ts"] }]
}