Ouch, that's just a crummy interview experience. If you're coming in with the understanding that .NET is your best language, seems odd they wouldn't allow that

Ouch, that's just a crummy interview experience. If you're coming in with the understanding that .NET is your best language, seems odd they wouldn't allow that, or at least make amends, such as letting you know in advance that it'll be about Jasmine, or using your own IDE.