Test for #4948 (RxDocument.get() on additonalProperty)

[adam-lynch]

This PR contains:

• IMPROVED TESTS

Describe the problem you have without this PR

This contains a test for #4948

[pubkey]

Hi @adam-lynch
I am not sure if this test is what you want it to be:
The test breaks because assert.strictEqual(myDocument.get('tags'), tags); throws.
But the tags object is never strictEqual to the thing you get from get('tags'), because RxDB will add getters for the population and observable fields.

Checking if the content is the same, works

 assert.deepStrictEqual(myDocument.get('tags').hello, tags.hello);
assert.deepStrictEqual(myDocument.get('tags').world, tags.world);

Also this is why toJSON().tags is strict equal, because toJSON() returns the plain data object, without any RxDB specific getters/setters.

[adam-lynch]

@pubkey ah yes, I've improved the test now. While what you said was true, it's still failing now; both .get('tags') and .tags have unexpected extra fields (additionalProperties and type).

[pubkey]

Can you rebase so that the CI can run?

[pubkey]

RxDB uses a prebuild constructor (per collection) to create the RxDocument from the documentData that comes out of the storage.
This constructor knows all getters/setters, ORM methods and so on. This makes creating the RxDocument much faster compared to deep-cloning the data and adding these things to each document object.
Therefore it does not add getters for fields that are not known at collection-creation time (=fields that are not in the schema).

The only other options would be the proxy API, but the Proxy API is so slow that I do not want to use it for accessing document properties, because the performance is so important at this.

So atm toJSON()... is the only way to get your additional properties. Atm I am not sure how this could be fixed. But I will check the code and see what can be done.

[adam-lynch]

OK I understand; if we want to use additionalProperties: true, we must access it via toJSON() / toMutableJSON().

[pubkey]

Yes, atm you need toJSON().
I see some options on how to fix that in the future, please leave this PR open.

[pubkey]

I did some performance tests and refactorings. This will be fixed in the next major version. #5063