persist-state: simple way to exclude keys from persistance

[hakimio]

Which @ngneat/elf-* package(s) are relevant/releated to the feature request?

persist-state

Description

Right now to exclude some keys from being saved, you have to do sth like the following:

persistState(store, {
        storage: myStateStorage,
        source: () => store
            .pipe(
                map(value => {
                    const {entities, ids, ...toSave} = value;
                    return toSave;
                })
            )
    }
);

It would be nice if there was a simpler way to specify keys to exclude.

Proposed solution

A simple exclude config would be nice:

persistState(store, {
    storage: myStateStorage,
    exclude: ['entities', 'ids']
});

Alternatives considered

Some custom RxJS operator similar to pluck but taking multiple keys:

persistState(store, {
        storage: myStateStorage,
        source: () => store
            .pipe(
                excludeKeys(['entities', 'ids'])
            )
    }
);

PS: I could create a PR but might need some suggestions for the simplest way to achieve this.

Do you want to create a pull request?

Yes

[hakimio]

On unrelated note: would be nice to have better source config documentation. Right now I had to take a look at the spec file to figure out how to use it.

[NetanelBasal]

It was like that in Akita, and I decided to give the consumer complete control.

[NetanelBasal]

You can share it on the docs

[hakimio]

Akita has the opposite: include config which is arguably less useful.
What do you think about the alternative solution?

[hakimio]

You can create a pure function in your application that does this.

Any suggestions how it could be implemented?

[NetanelBasal]

function excludeKeys(store, keys) {
  return store
            .pipe(
               map(value => {
                    // exclude functionality
                    return toSave;
                })
            )
}
persistState(store, {
        storage: myStateStorage,
        source: () => excludeKeys(store, ['foo', 'bar'])
    }
);

[NetanelBasal]

I don't mind getting a PR for this function as long as it's pure and tree-shakable.