I think you should start from the boiler-plate generated by Yoeman and convert to typescript step-by-step.
That’s should be enough to start.
Hi, I think there’s a generator by Jelte Lagendijk, you could have a look at that.
He mentioned it somewhere in the forum, but I can’t find the post again. I think it would be this one
The future is indeed in typescript, but also in React which will be replacing dojo eventually.
In fact some Mendix widgets are already using React right now see for example progress circle widget https://github.com/mendixlabs/progress-circle
I am sure that Mendix is preparing a scaffolding and tutorials for this new widget architecture. In the meantime a good starting point might be the progress circle widget I linked above.
Mendix is transitioning to Typescript and thus a React boilerplate including a generator will be made available. The new Widgets Team is working on getting this ready for production. I can't give you a time-frame yet (I am not part of that team), but documentation & tools will be available when Mendix 8 comes out.
In the mean time you can use one of the examples on Github, there are plenty of them. The mentioned generator I created was build for ES6 JS, not Typescript.