Integration: support z.looseRecord() and z.exactOptional()

[RobinTail]

Supporting the latest features of Zod 4.2 and 4.3 by the Integration generator

Summary by CodeRabbit

• New Features
  • Added a "loose" mode for Record types to allow more flexible key typing.
  • Improved handling of optional vs. undefined for interface properties with a configurable option and broader support for optional-like wrapped types.
• Tests
  • Expanded test coverage for additional Zod features (loose records, exact-optional behavior, composite schemas).
• Chores
  • Updated changelog with the new integration details (v26.3.0).

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds a hasUndefined option to TypeScript property generation, separates optional/undefined computation in schema generation, adds support for loose Record schemas, extends wrapped-type handling to include exact-optional variants, and updates tests and changelog.

Changes

Cohort / File(s)	Summary
TypeScript API parameter enhancement express-zod-api/src/typescript-api.ts	makeInterfaceProp signature now accepts hasUndefined?: boolean (defaults to isOptional). Property signature construction uses hasUndefined to decide whether to union the type with undefined.
Schema generation handlers express-zod-api/src/zts.ts	onObject computes and forwards both isOptional and hasUndefined to makeInterfaceProp. onRecord supports def.mode === "loose" by returning an intersection with a looser key type. onWrapped includes z.core.$ZodExactOptional among optional-like wrappers.
Tests express-zod-api/tests/zts.spec.ts	Adds test cases exercising looseRecord, exactOptional(), and additional example fields (codec/slug/hex/hash/xor) to cover the new/changed Zod features.
Changelog CHANGELOG.md	Adds v26.3.0 entry documenting support for z.looseRecord() and handling of exact-optional/exactOptional variants.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Memory usage optimization #3139: Related edits to typescript-api.ts modifying TypeScript API surface and makeInterfaceProp placement/behavior.
• Fixing recursive prop issue and supporting ZodNonOptional #2696: Related changes to zts wrapped/optional handling and exact-optional behavior.

Suggested labels

refactoring

Poem

🐇 I nibbled types and found a clue,
hasUndefined now hops into view.
Loose records scamper, exacts tuck in tight,
Tests clap their paws in the moonlight. 🥕

Pre-merge checks

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and concisely describes the main changes: adding support for two specific Zod features (z.looseRecord() and z.exactOptional()) in the Integration generator, matching the primary content of the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

---

📜 Recent review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 1ce8eee and 9a22b97.

📒 Files selected for processing (1)

• CHANGELOG.md

🚧 Files skipped from review as they are similar to previous changes (1)

• CHANGELOG.md

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: build (22.12.0)

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[coveralls-official]

coverage: 100.0%. remained the same
when pulling 9a22b97 on feat-zts-upd-2025-12-31
into 486fd36 on master.

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

CHANGELOG.md (1)

5-9: Improve phrasing in the changelog entry.

The phrase "Object properties made by" on line 9 is slightly awkward. Consider "Object properties created by" for consistency and clarity (which aligns with the phrasing used elsewhere in the codebase and PR context).

Current:

- Object properties made by `z.exactOptional()` or `ZodType::exactOptional()` method.

Suggested:

- Object properties created by `z.exactOptional()` or `ZodType::exactOptional()` method.

📜 Review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 9b891d2 and 1ce8eee.

📒 Files selected for processing (1)

• CHANGELOG.md

🧰 Additional context used

🧠 Learnings (6)

📓 Common learnings

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 2546
File: express-zod-api/tests/form-schema.spec.ts:31-31
Timestamp: 2025-05-27T19:27:13.492Z
Learning: Zod version 3.25.0 and later expose the Zod v4 API through the special import paths "zod/v4" and "zod/v4/core", allowing v4 features like .loose() to be used even when the package.json dependency shows a 3.x version.

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 2697
File: CHANGELOG.md:5-5
Timestamp: 2025-06-02T21:11:20.768Z
Learning: In the express-zod-api repository, RobinTail follows a release workflow where package.json version is only updated on the master branch after merging all planned release changes. Changelog entries may show future version numbers while package.json remains at the previous version during feature development, and this is intentional workflow, not a version inconsistency that needs to be flagged.

📚 Learning: 2025-05-27T19:27:13.492Z

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 2546
File: express-zod-api/tests/form-schema.spec.ts:31-31
Timestamp: 2025-05-27T19:27:13.492Z
Learning: Zod version 3.25.0 and later expose the Zod v4 API through the special import paths "zod/v4" and "zod/v4/core", allowing v4 features like .loose() to be used even when the package.json dependency shows a 3.x version.

Applied to files:

• CHANGELOG.md

📚 Learning: 2025-05-27T20:08:50.699Z

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 2546
File: express-zod-api/src/metadata.ts:5-13
Timestamp: 2025-05-27T20:08:50.699Z
Learning: The `_zod` property in Zod v4 schemas is officially documented and recommended for library authors to differentiate between Zod 3 and Zod 4 schemas at runtime, despite the underscore prefix. This is explicitly mentioned in Zod's library authors documentation and is not a private internal property.

Applied to files:

• CHANGELOG.md

📚 Learning: 2025-08-05T14:43:24.702Z

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 2869
File: zod-plugin/package.json:42-44
Timestamp: 2025-08-05T14:43:24.702Z
Learning: Zod version 4 has been officially released and is stable. As of August 2025, the latest published version is 4.0.14 (published July 30, 2025). Zod v4 is available on npm and can be used in peer dependencies with version constraints like "^4.0.0".

Applied to files:

• CHANGELOG.md

📚 Learning: 2025-05-27T20:27:17.015Z

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 2546
File: express-zod-api/src/json-schema-helpers.ts:1-3
Timestamp: 2025-05-27T20:27:17.015Z
Learning: The JSONSchema type is not exported from the main "zod" module and must be imported from "zod/v4/core" when using Zod v4. This is acceptable for type-only imports as they don't create runtime dependencies.

Applied to files:

• CHANGELOG.md

📚 Learning: 2025-08-01T09:48:13.742Z

Learnt from: RobinTail
Repo: RobinTail/express-zod-api PR: 0
File: :0-0
Timestamp: 2025-08-01T09:48:13.742Z
Learning: In express-zod-api, when migrating from Zod v3 to v4, the correct approach for internal type imports is to change from `import type { $ZodType } from "zod/v4/core"` to `import { z } from "zod"` and then use `z.core.$ZodType`. The zod/v4/core module is reexported as z.core by the main zod package, making this a valid and working approach.

Applied to files:

• CHANGELOG.md

[RobinTail]

🏁