fix: type params slot assignments

[pullfrog]

Summary

• fix the generated params helper by using a wider internal slot map type for mutable indexed assignments
• keep the returned params shape unchanged for existing client consumers
• regenerate affected snapshots and examples

Closes #3862

Testing

• pnpm turbo run typecheck --filter=@hey-api/openapi-ts
• pnpm exec vitest run --project @hey-api/openapi-ts src/plugins/@hey-api/client-core/__tests__/params.test.ts
• pnpm exec vitest run --update --project @test/openapi-ts --project @test/openapi-ts-sdks --project @test/openapi-ts-tanstack-query-v5 --project @test/openapi-ts-valibot-v1 --project @test/openapi-ts-zod-v3 --project @test/openapi-ts-zod-v4
• pnpm examples:generate
• pnpm turbo run typecheck --filter=@test/openapi-ts
• pnpm exec tsc --ignoreConfig --strict --stableTypeOrdering --target ES2022 --module ESNext --moduleResolution Bundler --lib ES2022,DOM,DOM.Iterable --noEmit packages/openapi-ts-tests/main/test/__snapshots__/3.1.x/clients/@hey-api/client-fetch/default/core/params.gen.ts
• pnpm lint

  ^{｜ View workflow run ｜ via Pullfrog ｜ Using GPT ｜ 𝕏}

[bolt-new-by-stackblitz]

Run & review this pull request in StackBlitz Codeflow.

[changeset-bot]

🦋 Changeset detected

Latest commit: 9208584

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

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
web	Ready	Preview, Comment	May 27, 2026 8:51pm

[pkg-pr-new]

Open in StackBlitz

@hey-api/codegen-core

npm i https://pkg.pr.new/@hey-api/codegen-core@3946

@hey-api/json-schema-ref-parser

npm i https://pkg.pr.new/@hey-api/json-schema-ref-parser@3946

@hey-api/nuxt

npm i https://pkg.pr.new/@hey-api/nuxt@3946

@hey-api/openapi-ts

npm i https://pkg.pr.new/@hey-api/openapi-ts@3946

@hey-api/shared

npm i https://pkg.pr.new/@hey-api/shared@3946

@hey-api/spec-types

npm i https://pkg.pr.new/@hey-api/spec-types@3946

@hey-api/types

npm i https://pkg.pr.new/@hey-api/types@3946

@hey-api/vite-plugin

npm i https://pkg.pr.new/@hey-api/vite-plugin@3946

commit: 9208584

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 37.40%. Comparing base (7121e6e) to head (9208584).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3946   +/-   ##
=======================================
  Coverage   37.40%   37.40%           
=======================================
  Files         654      654           
  Lines       22456    22456           
  Branches     6538     6531    -7     
=======================================
  Hits         8400     8400           
  Misses      11397    11397           
  Partials     2659     2659           

Flag	Coverage Δ
unittests	37.40% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.