Function ExportDefaultDeclaration

src/babel.dev.js:104–132

(path, state)

  return {
    visitor: {
      ExportDefaultDeclaration(path, state) {
        const { file } = state;
        // Default exports with names are going
        // to be in scope anyway so no need to bother.
        if (path.node.declaration.id) {
          return;
        }

        // Move export default right hand side to a variable
        // so we can later refer to it and tag it with __source.
        const id = path.scope.generateUidIdentifier('default');
        const expression = t.isExpression(path.node.declaration)
          ? path.node.declaration
          : t.toExpression(path.node.declaration);
        path.scope.registerDeclaration(
          path.insertBefore(t.variableDeclaration('const', [t.variableDeclarator(id, expression)]))[0],
        );
        path.node.declaration = id; // eslint-disable-line no-param-reassign

        // It won't appear in scope.bindings
        // so we'll manually remember it exists.
        state[REGISTRATIONS].push(
          buildRegistration({
            ID: id,
            NAME: t.stringLiteral('default'),
            FILENAME: t.stringLiteral(file.opts.filename),
          }),
        );
      },

      Program: {
        enter({ scope, node }, state) {