b) is left as an exercise for the reader, to pick dependencies and protocols based on their merits, one consideration being support for types. But TypeScript do

b) is left as an exercise for the reader, to pick dependencies and protocols based on their merits, one consideration being support for types. But TypeScript does appear to be more than types alone, so there are other benefits. See also: AngularDart, which also has the same "b)" problem, but worse as it doesn't interact as easily with existing JS.