babel/packages/babel-plugin-syntax-optional-catch-binding/src/index.js

import { declare } from "@babel/helper-plugin-utils";

export default declare(api => {
  api.assertVersion(7);

  return {
    name: "syntax-optional-catch-binding",

    manipulateOptions(opts, parserOpts) {
      parserOpts.plugins.push("optionalCatchBinding");
    },
  };
});