Provide way to omit __interal__ from store on get

[willium]

The internal key causes some problems, both during write (#114) and at read (can't trust MyStore.keys() or MyStore.values() without omitting internal). We should at least export the variable so the client can manually omit it (and at best, provide a more ergonomic pattern—perhaps a WeakMap?)

[willium]

In my subclass, I do this:

	public get current(): T {
		return omit(this.store, "__internal__") as T
	}

	public set current(value: T) {
		const { __internal__ } = this.store
		this.store = {...value, __internal__ } as T
	}

which seems to work but isn't ideal (and at the very least, I'd love import INTERNAL_KEY rather than hardcode it here).

[sindresorhus]

I'm not interested in exposing internal implementation details. This should be properly fixed by making changes to this.store not change __internal__. This can be done by making this.store be a facade for an internal this._store and have this.store be getter/setters that handles ignoring __internal__.

[sindresorhus]

(and at best, provide a more ergonomic pattern—perhaps a WeakMap?)

Cannot use WeakMap as the __internal__ key needs to be persisted.

[willium]

fair enough. do you think the changes to the getter/setter goes beyond what I did in my subclass?

[sindresorhus]

I think that should be enough as this.store is used for any reading/writing.

[willium]

should I submit a PR with this change?

[sindresorhus]

Yes, that would be great. Needs some tests too.

[willium]

It's unfortunately not going to be super simple as migrations (or at least their tests) rely on being able to lookup migrations by the internal property (for example this, relies on .get() which in turn uses .store). I'm not sure your preferred strategy for exposing/mocking private methods for tests, but if you're willing to remove the ability to .get() data off the internal key, we could introduce some kind of method _getInternal() that doesn't use .get store, though in order to use it in the tests it'd have to be public...

[willium]

We could also do some any hacking in the tests

[sindresorhus]

we could introduce some kind of method _getInternal() that doesn't use .get store, though in order to use it in the tests it'd have to be public...

Sounds good. We can make it public only when if (process.env.NODE_ENV === 'test') {.

[sindresorhus]

Friendly bump :)

[sindresorhus]

Closing for lack of activity.