feat: combine equalTo clauses with clauses

[sadakchap]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

equalTo query overrides any existing clauses before it. For e.g.

let q = new Parse.Query('MyClass');
q.greaterThan('age', 10);
q.equalTo('age', 9);
// this will override $gt query and will result something like this where: { age : 9 }

Related issue: #1372

Approach

After following through #1372 and parse-community/parse-php-sdk#476 and #1372 (comment).

Using this.addCondition(key, $eq, value) instead this.where[key], so that equalTo clause can be combined with other clauses and vice-versa.

TODOs before merging

• Add tests
• Add entry to changelog
• Add changes to documentation (guides, repository pages, in-code descriptions)

[davimacedo]

@sadakchap do you mind to look at the failing tests?

Overall I like the idea. @dplewis what do you think?

[mtrezza]

have added only a failing test case.

@sadakchap it seems you have actually also added the fix in this PR, correct? If so, is this ready for review? I would like to add the related dashboard feature with the null filter.

[sadakchap]

If so, is this ready for review? I would like to add the related dashboard feature with the null filter.

Thanks @mtrezza , I think it still has some failing tests. I will try to fix those during this weekend and will let you know 🙂

[parse-github-assistant]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[sadakchap]

@mtrezza Thanks for following up & waiting.

About failing test cases. Only Live Query test are failing as they depend on parse-server to fire events. We will need to update parse-server to send events for $eq queries in order to fix all failing test case.

[sadakchap]

Here's the pr with added support for $eq query for LiveQuery.

@mtrezza @davimacedo @dplewis, would really like to hear your thoughts about it?

[mtrezza]

This comment seems to be a leftover?

[sadakchap]

Sure, will remove.

[sadakchap]

Will update the pr once all checks are passing.

[mtrezza]

Should all these tests be modified? That means the original syntax would not be tested anymore?

[sadakchap]

Yes, all test are modified. And yes, original syntax would not be tested anymore as it will always make any equalTo query with this updated syntax { $eq: '' }

[mtrezza]

Could that be a breaking change for existing deployments?

[sadakchap]

I don't see it as a breaking change, as it will just change the syntax of query for equalTo, everything else should be same.

For adding equalTo query, we still would be doing same thing.

q.equalTo('age', 10); // same implementation, just query that will be sent is of new syntax.

[mtrezza]

Does this mean the query sent to the DB has a different syntax, or only the query sent to Parse Server?

[mtrezza]

It seems strange that this results in $eq:small and $exists:false, isn't that a contradiction?

The comment assumed: equalTo('key', undefined) resolves to 'does not exist'
But in this case it just adds dne to the query, which probably results in a different query sent to the DB?

[sadakchap]

Yes, It is contradiction. 😕

Suggestion: Maybe we can make $exists override $eq clause.

Problem: this pr is in response to this #1372, which was created due to this pr, where we were trying to make a query something like this(for filtering values which are null & exists)

where: { age: { $eq: null, $exists: true } }

which again won't be possible if $exists can't be combined with $eq

[mtrezza]

This also looks strange

[sadakchap]

#1373 (comment)