[undo/redo]: clearStack is executed before the store is modified

[richardliebmann]

Hi,

if I execute clearStack directly in a store method after reverting / initializing a part of the store, the clearStack is executed before the store is modified and the undo/redo stack gets the change as initial value.

export const EditorStore = signalStore(
    { providedIn: 'root' },
    ...
    withUndoRedo({
        maxStackSize: 100,
        keys: ['selectedFile']
    }),
    withMethods((store) => {
      ...
      selectFile(file: ProjectFile) {
          patchState(store, {
              selectedFile: selected,
          });
    
          store.clearStack();
      },
      ...
});

The problem may be that clearStack is executed synchronously, whereas the undo/redo uses an effect that is executed asynchronously.

https://github.com/angular-architects/ngrx-toolkit/blob/399903d198cd8be3ff3ad0df4de5843de855167f/libs/ngrx-toolkit/src/lib/with-undo-redo.ts#L139C9-L139C15

The solution might be to use watchState instead of effect, which is executed synchronously.

Am I right? Should I create a pull request with this fix?

[GregOnNet]

Hi @richardliebmann,

I had a similar issue and provided a PR, which has not been released, yet.
#186

However, you encountered another root-cause than mine.
Maybe it is worth having a look at it.

Also bringing watchState to the table makes sense.

Could you please check if #185 is related to your finding?

[GregOnNet]

In my opinion using watchState instead of effect is a valuable change.
This would allow to make the unit-tests synchronous. Currently, they are asynchronous.

[richardliebmann]

Hi @GregOnNet,

Thank you for your confirmation. I don't think your problem is related to this one and it has different effects.

Hopefully the bug fixes will be released soon :-)

[rainerhahnekamp]

@richardliebmann, it would be great if you add a PR for that.

[richardliebmann]

Hi @rainerhahnekamp: done #207