babel-plugin-extendable-error.js

module.exports = function(babel) {
  const { types: t } = babel;
  return {
    visitor: {
      ClassDeclaration(path, parent) {
        if (path.isClassDeclaration()) {
          const className = path.node.id.name;
          if (!path.node.superClass || path.node.superClass.name !== 'Error') {
            return;
          }
          path.insertAfter(
            t.expressionStatement(
              t.assignmentExpression(
                '=',
                t.memberExpression(
                  t.memberExpression(
                    t.identifier(className),
                    t.identifier('prototype'),
                  ),
                  t.identifier('name'),
                ),
                t.stringLiteral(className),
              ),
            ),
          );

          path.insertAfter(
            t.expressionStatement(
              t.callExpression(
                t.memberExpression(
                  t.identifier('Object'),
                  t.identifier('defineProperty'),
                ),
                [
                  t.memberExpression(
                    t.identifier(className),
                    t.identifier('prototype'),
                  ),
                  t.stringLiteral('name'),
                  t.objectExpression([
                    t.objectProperty(
                      t.identifier('enumerable'),
                      t.booleanLiteral(false),
                    ),
                  ]),
                ],
              ),
            ),
          );
        }
      },
    },
  };
};