When I use Rollup from [Angular 2 docs](https://angular.io/docs/ts/latest/cookbook/aot-compiler.html) I get an error when trying to execute rollup config js file:

```
 Unexpected token
    node_modules/rxjs/util/isArrayLike.js (2:78)
    1: "use strict";
    2: var isArrayLike_1 = function (x) { return x && typeof x.length === 'number'; });
                                                                                     ^
3: //# sourceMappingURL=isArrayLike.js.map

```

When I look into `isArrayLike.js` file in `rxjs` repo, I can see that file contains the following code:

`exports.isArrayLike = (function (x) { return x && typeof x.length === 'number'; });`

Looks like on tree shaking step rollup removes one of the brackets `this one -->(function (x)` and tree shaking fails.

If I manually remove last parenthesis in `rxjs/isArrayLike.js` file, rollup works fine.

Is there any way to fix this issue?

`"rollup-plugin-commonjs": "^7.0.0"
 "rxjs": "^5.2.0"`