Fixing widespread edge case of nullable dates in required fields in transformers

[Freddis]

Right now date transformer doesn't take into account nullable dates, which is quite a widespread case. It produces this code:

obj.nullableDate =  new Date(obj.nullableDate);

I suppose everybody is experienced enough to see it's gonna give your consumers a data corruption in no time.

The PR doesn't account for all possible cases, only for Date | null.

I'm not sure if the author of the repo is reading through PRs, but if you do, I tell you what:

The plugin system right now is in absolutely disastrous state. You won't get much help by outright lying in your docs.

We are not in the same boat! Your built-in plugins do communicate with each other somehow and they have access to modules that are not exported from the project.

The only reason I'm sending this PR is that I don't want to have your project hanging in my repo with source files. Under different circumstances I would never sent a PR after spending 6 hours on a 3 minute fix because I believed you that we are in the same boat. We clearly are not.

I can't imagine how many others tried to write their own plugins only to find out you can't do anything with them. To replicate the behavior of transformers you need to resort to copying and pasting files from original code and in the end SDK plugin simply ignores yours, because yours is not "@hey-api/transformers".

Decouple your plugins and the project is going to bloom. For now, you can at least allow to set the same names as built-in plugins for your own plugins to create an override, so we could copy / paste the code and fix problems there or tweak the behaviours.

EDIT AFTER FINALIZING FIX:

Turned out that the original transformers for nullables were fine in what schemas they supposed to pick up. The problem was in discriminating against required fields in object schemas. Required means that value is present, but doesn't guarantee that the value is not nulish.

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🦋 Changeset detected

Latest commit: d7af22c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@hey-api/openapi-ts	Patch

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[mrlubos]

@Freddis thank you for the pull request! Rest assured I read every comment. This package is still in v0 so expect to find some rough edges (as you successfully did)

[Freddis]

@mrlubos thank you for your response, it's reassuring. Other than my issues with the plugin system, the library works just like a charm. It provides a solid out-of-the-box experience and I'm really enjoying using it at work and in my own projects.

Looking at how tests went, I'm seeing that the problem with dates is not as bad as I've expected. There are 2 ways of how union types can be described in openapi:

 updatedAt:
    type:
      - string
      - "null"
    format: date-time

or

"bar": {
            "anyOf": [
              {
                "type": "string",
                "format": "date-time"
              },
              {
                "type": "null"
              }
            ]

For the latter case you have a test against, which is good. Unfortunately my fix conflicts with this test and creates unnecessary code duplication in resulting transformer for such case.

I'll try to fix it tomorrow so you have both cases covered with clean output code.

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commit: d7af22c

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Codecov Report

Attention: Patch coverage is 0% with 22 lines in your changes missing coverage. Please review.

Project coverage is 24.14%. Comparing base (c8eb3d6) to head (d7af22c).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...api-ts/src/plugins/@hey-api/transformers/plugin.ts	0.00%	22 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1917      +/-   ##
==========================================
- Coverage   24.15%   24.14%   -0.01%     
==========================================
  Files         193      193              
  Lines       26851    26861      +10     
  Branches      787      787              
==========================================
  Hits         6486     6486              
- Misses      20290    20300      +10     
  Partials       75       75              

Flag	Coverage Δ
unittests	24.14% <0.00%> (-0.01%)	⬇️

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[mrlubos]

Looks good man, thank you!