regeneratorRuntime is not defined

[adilsoncarvalho]

Hi there.

Do you guys have an option on how to deal with the regeneratorRuntime is not defined issue?

I updates your index.ts and added the following method into the C class:

async metodo() {
  return "ok";
}

After building it and trying to invoke the transpiled code using node ./lib/index I got the following error:

$ node
> require("./lib/index")
ReferenceError: regeneratorRuntime is not defined
    at /Users/adilson/dev/TypeScript-Babel-Starter/lib/index.js:46:7
    at /Users/adilson/dev/TypeScript-Babel-Starter/lib/index.js:64:6
> 

That's because of this part of the generated code that requires regeneratorRuntime to work:

_createClass(C, [{
  key: "metodo",
  value: function () {
    var _metodo = _asyncToGenerator(
    /*#__PURE__*/
    regeneratorRuntime.mark(function _callee() {
      return regeneratorRuntime.wrap(function _callee$(_context) {
        while (1) {
          switch (_context.prev = _context.next) {
            case 0:
              return _context.abrupt("return", "ok");

            case 1:
            case "end":
              return _context.stop();
          }
        }
      }, _callee, this);
    }));

    return function metodo() {
      return _metodo.apply(this, arguments);
    };
  }()
}]);

All the post I saw so far mention those two options:

• @babel/plugin-transform-regenerator which I could not manage to get it working

• to add @babel/polyfill that actually works but it is a terrible option when coding a new lib as there is no central import point, making the require to happen on each file

Do you have any tips on that?

Thanks!

[mng-au]

I am able to get regeneratorRuntime is not defined issue resolved today. I will note down what I found here.

Instead of @babel/plugin-transform-regenerator, add @babel/plugin-transform-runtime and @babel/runtime.

yarn add -D @babel/plugin-transform-runtime
yarn add @babel/runtime

Then add @babel/plugin-transform-runtime to .babelrc, and should look like the following:

{
    "presets": [
        "@babel/env",
        "@babel/typescript"
    ],
    "plugins": [
        "@babel/plugin-transform-runtime",
        "@babel/proposal-class-properties",
        "@babel/proposal-object-rest-spread"
    ]
}

Please let me know does it fix your issue with regeneratorRuntime is not defined. I will upload a small working webpack solution to github if necessary.

All the best.

References:

1. https://babeljs.io/docs/en/next/babel-plugin-transform-runtime

[matthias-ccri]

Does babel always transform async/await statements to regeneratorRuntime calls? If so — should this be added to the recommended setup in the README, given that async/await is a core part of typescript?