E0177: React/JSX is not allowed in vanilla JavaScript code

Vanilla JavaScript does not support JSX syntax (used in React code). It is a syntax error to create a JSX element or JSX fragment in vanilla JavaScript:

ReactDOM.render(
  <h1>Hello, world!</h1>,
  document.getElementById('root')
);

To fix this error, use React.createElement instead of JSX syntax:

ReactDOM.render(
  React.createElement('h1', null, 'Hello, world!'),
  document.getElementById('root')
);

Alternatively, use --language=javascript-jsx instead of --language=javascript.

Introduced in quick-lint-js version 0.6.0.

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