Version 1.0.15+2 and SDK 0.5.9_r22879 not working when compiled to JavaScript

[patrickhempel]

My Code is running as expected in Dartium but when I try to run the compiled JavaScript version following error arise in my browser log.

Uncaught NoSuchMethodError : method not found: 'call' 
Receiver: Instance of 'JsonObject__extractElements_closure'
Arguments: [Instance of 'LinkedHashMap'] 

I was able to pin down this error to following code.

JsonObject response = new JsonObject.fromJsonString( _request.responseText);

My Application is talking with a JSON-RPC API und tries to create a JsonObject from the response string.

After all, my code ran in previous version of the SDK.