Inheriting AMD/UMD classes when using AMD

[viveleroi]

Repo: https://github.com/viveleroi/rollup-amd-inherit-bug

I have a class which extends EventEmitter2, and they distribute umd. When our bundle is used with requirejs/AMD, the createCommonjsModule doesn't return anything.

Our source can simply be this:

import EventEmitter2 from 'eventemitter2';

export default class Test extends EventEmitter2 {}

In EventEmitter2 code, and in the bundled output, we get:

if (typeof define === 'function' && define.amd) {
     // AMD. Register as an anonymous module.
    define(function() {
      return EventEmitter;
    });
  }
...

Problem is, the createCommonjsModule doesn't handle this. The output assigns the returned value of that method, but in this case, it's undefined.

var eventemitter2 = createCommonjsModule(...
// => undefined

So when eventemitter2 is passed to the inherits call (inherits(Test, _EventEmitter);) it throws an error Super expression must either be null or a function, not object

[Rich-Harris]

Good news! This is fixed in 6.0.0, via #144 – just tested the repro and if you update this plugin it should all work.

[viveleroi]

I missed that was a duplicate, my bad. Glad to hear, I'll try it out.