message: Enable ESLint rule to require defined components in JSX
diff: @@ -47,6 +47,9 @@ module.exports = {
  }],
  "react/jsx-key": ["error"],
  + // Components in JSX should always be defined.
  + "react/jsx-no-undef": "error",
  +
  // Assert no spacing in JSX curly brackets
  // <Element prop={ consideredError} prop={notConsideredError} />
  //
  