Undeclared parameters are implicitly "any". You don't need nearly this much code to break. This is equivalently broken: var x: any = {}; x.foo(); Here's the

Undeclared parameters are implicitly "any". You don't need nearly this much code to break. This is equivalently broken: var x: any = {}; x.foo(); Here's the typesafe way: http://tryflow.org/#b5f826e03045f64084cfc74398270e85 http://tryflow.org/#b5f826e03045f64084cfc74398270e85