feat(expressionBuilder): add ability to reference an attribute

[craPkit]

Implements #142

Supports referenced attributes on FilterExpressions' fields 'eq' | 'ne' | 'lt' | 'lte' | 'gt' | 'gte'.

How To:

TestEntity.update({
  // ...
  conditions: { attr: 'a', eq: { attr: 'b' } }
});

Positive and negative tests included.

[darbio]

Can you add this to the README too?

[rbdmorgan]

@craPkit this is a nice feature would be great to see it merged 😄

I added support for nested attribute conditions and filters in #288, #294 and #297 so you'll need to merge main and adapt this PR accordingly but shouldn't be too much work and the collective changes will complement each other nicely 🙏🏼

[craPkit]

@craPkit this is a nice feature would be great to see it merged 😄

I added support for nested attribute conditions and filters in #288, #294 and #297 so you'll need to merge main and adapt this PR accordingly but shouldn't be too much work and the collective changes will complement each other nicely 🙏🏼

Main is merged now. I haven't implemented nested attributes in my AttrRefs though, since, being ignorant of your feature, I wasn't sure which cases need to be covered.

[naorpeled]

Hey @craPkit ,
first of all, thanks for creating this PR, you're awesome!

Sorry for the late reply to this.
Will review this PR in a bit and will aim to merge this asap, this is a great addition to the library!

[naorpeled]

Overall looks good,
left one small nit comment.

Let's also add a validation and a test that begins_with is not used with an AttrRef because it's currently generating an invalid expression.

Once that's addressed, this PR will be ready to merge 😎