Online tool unable to generate dart code

Hi there. First of all thanks for trying to make this figma to flutter plugin a reality.

I've been trying it out for our component library we have been designing in figma. However I'm unable to actually get the code with the tool. I've provided an Figma Access token and the file_key from the url.

When I then select a component in the resulting list and click the generate dart code button nothing happens.

I've openeded the developer console and I'm see the following error popup:
`js_helper.dart:1764 Uncaught TypeError: Cannot read property '$indexSet' of undefined
at FigmaGenerator__generateWidgets_closure.call$2 (component.dart:19)
at JsLinkedHashMap.forEach$1 (linked_hash_map.dart:202)
at FigmaGenerator._generateWidgets$4$dataClassImport$withComments$withDataClasses (file.dart:162)
at FigmaGenerator.generateComponents$4$dataClassImport$withComments$withDataClasses (file.dart:81)
at FigmaGenerator.generateComponents$2$withComments (file.dart:67)
at main.dart:58
at _wrapJsFunctionForAsync_closure.$protected (async_patch.dart:335)
at _wrapJsFunctionForAsync_closure.call$2 (async_patch.dart:359)
at Object._asyncStartSync (async_patch.dart:251)
at main_generateCode.call$0 (main.dart:48)`

I'm using chrome Version 78.0.3904.97 (Official Build) (64-bit) on a Mac OSX 10.14.4(18E226) (Mojave)