从redux减速器获取结果

Question

I have a function that is called from external code. Its effect should be to create an object in my redux store based on passed data, and to return the object's id as a handle for future updates:

const addNode = (data) => {
    dispatch(createNode(data));
    ...
    return createdNodeId;
}

My problem is: how to get the id of the object that was created as a result of the dispatched action?

The dispatch returns the full state, not just the new object. I see a couple of options, but I'm unsure which one would be best...

Option 1: Generate and pass ID

Generate the id myself in addNode and pass it into createNode(...) with the rest of the data.

That's probably the easiest from a practical point of view, but I find it horrible from a conceptual standpoint. The formerly internal id generation strategy is suddenly exposed in my function, and what's more, depending on the id strategy, I might have to deal with all kinds of id clashes and/or synchronization to avoid those.

Option 2: Extract ID from result state

I guess it would be possible to extrapolate the new node from the result state. But that can get very complicated very quickly, never mind slow...

Option 3: Pass ID back in action

Actions are supposed to be immutable. But what would actually happen if I would designate a "result" property in my action that the reducer would write to to pass out the desired information? In my understanding this should work fine, as long as the "result" property is never treated as part of the action's input payload by the reducer.

This is still a bit dodgy, since the action is now partially mutable. But given the other options, it's my favorite right now.

Edit: A similar question was asked before, but the answer was to change the reducer to avoid the need of the result. Sadly, that's not an option here.

Answer 1

It sounds like it's currently your reducer that is generating the id for the newly created object. If that' correct, then I'm guessing its a fairly simple, synchronous process. It also doesn't seem right to me. I would expect the reducer to only act on the data passed in the action, which should include the new object's id. So I would suggest option 4..

Break out the code that generates the id from the reducer into it's own space. Use that code to include the id in the action dispatched to create the new object, either from any code that dispatches the action, or from the action creator itself. Return the id from your function.

const addNode = (data) => {
  const action = createNode(data);
  dispatch(action);
  ...
  return action.payload.id;
}