Best way to encapsulate a repeated large state update?

[julianeden]

One issue I run into with pullstate that I haven't found a good solution to is when I want to set a significant amount of state based on the value of a piece of state that is being changed.

As always this is best shown by example.

const resultOfUserInput = getUserInput();
MyStore.update(s => {
  s.someState = resultOfUserInput;
  if (resultOfUserInput === MyEnum.SomeValue) {
     s.x = ...;
     s.y = ...;
     s.z = ...;
  }
});

If there are 5 places in my project where x, y, and z are updated as a result of someState changing, then it's nice to put the update to x/y/z in a function instead of repeating that block 5 times. So say I have this:

const updateXYZ = () => {
 MyStore.update(s => {
     s.x = ...;
     s.y = ...;
     s.z = ...;
 });
};

The issue is that I cannot do this, because I can't nest store update calls:

const resultOfUserInput = getUserInput();
MyStore.update(s => {
  s.someState = resultOfUserInput;
  if (resultOfUserInput === MyEnum.SomeValue) {
     updateXYZ();
  }
});

I haven't found a good workflow for this. Does anyone know of one?