Paste event e.clipboardData.types not working with Firefox

[damien-git]

This code fails with Firefox (e is a paste event):
h.DataTransfer data = e.clipboardData; if (data.types.contains('text/html')) { ... }
Error: TypeError: t1.contains$1 is not a function
This looks like a bug in dart2js (getInterceptor does not recognize DOMStringList).

Using Firefox 49.0 and Dart 1.20.1.

[travissanderson-wf]

I just ran into the same thing, I'm not seeing a way to even work around it when we know we're running in Firefox either. data.types prints to the console as [Object DOMStringList] which is the JS type, can't be cast to the Dart DomStringList type.

[travissanderson-wf]

fwiw, you can still query for specific known formats so if you know you're interested in plain text or HTML, that is still doable