[Q] How to add extra container and modify creation

[ParadiseFallen]

Hi. I have a questuion about extending mst.

Im using kinda MVVM with react. so i need to pass dependencies to my models.
And i dont want to use env (has no strong type)

So im woundering how to create .dependencies() method for types.model builder and add types from dependencies to required params on create method

[EmilTholin]

Hi @ParadiseFallen!

You could e.g. create your own views extension that supplies a typed version of the environment:

import { getEnv, IStateTreeNode, types } from "mobx-state-tree";

type Env = {
  baz: string;
};

const withEnv = (self: IStateTreeNode) => ({
  views: {
    get env() {
      return getEnv<Env>(self);
    }
  }
});

const Model = types
  .model({
    foo: "bar"
  })
  .extend(withEnv)
  .actions((self) => ({
    afterCreate() {
      console.log(self.env.baz);
    }
  }));

const model = Model.create({}, { baz: "qux" });