TypeScript: Project compiles OK but hangs when --watch is added

Hey @benjaminjackman @pelotom I’m struggling with similar issues

Something that really helped with spinning up watch is to mask MST models behind interfaces, especially for composited models. (is a similar manner to your examples )

i didn’t check how its effect decelerations emits, just tsc -w startup times (from forever to 10 secs) and im still playing with it.

A quick and minimal example:

export type ForDirectExtend<T> = T;

const MyAModelInferred = types.model("MyAModel", {
  items: types.array(types.string)
});

interface MyAModelType extends ForDirectExtend<typeof MyAModelInferred> {}

// now MyAModel is fast!
const MyAModel: MyAModelType = MyAModelInferred;


// Now even MyBModelInferred is not very slow, becouse its referencing the "fast" MyAModel and not the inferred thing
const MyBModelInferred = types.model("MyBModel", {
  somethingsomething: types.map(MyAModel)
});

interface MyBModelType extends ForDirectExtend<typeof MyBModelInferred> {}

const MyBModel: MyBModelType = MyBModelInferred;

And if we could hint typescript to create intermediate type names instead all of it, that would be great!

I made a gist that describes how to use chokidar to call tsc --noEmit whenever a file changes in case anyone stumbles into this ticket:

And it is definitely ultimately the structural decomposition of classes that ends up as the issue here (aggravated by the combinatoric expansion masked via the conditionals) - I experimentally disabled that feature in our declaration emitter (it is just one of the flags set at the top), and while it introduced some errors (as some types became unprintable), it also let it build pretty much instantly with declaration on. 😦