Migrate to typescript 6 and tsdown

[Robin-w151]

Typescript + tsdown migration

Requirements

• Typescript 6 is released

Summary by CodeRabbit

• New Features

  • Pre-release version 0.4.0-next.3 now available with TypeScript 6 support

• Updates

  • Migrated to new build tooling for improved module bundling
  • Updated package export paths for enhanced compatibility

• Chores

  • Updated development dependencies including TypeScript, ESLint, and testing tools

[changeset-bot]

🦋 Changeset detected

Latest commit: c209bb1

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

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

[coderabbitai]

📝 Walkthrough

Walkthrough

A release preparation update that migrates the build tooling from tsup to tsdown, adds four changeset entries documenting different release aspects, bumps the package version to 0.4.0-next.3, updates TypeScript to version 6.0.2, adjusts package export paths to use .mjs and .d.mts extensions, and updates the CHANGELOG with new unreleased version entries.

Changes

Cohort / File(s)	Summary
Release Management .changeset/brave-yaks-argue.md, .changeset/cozy-swans-add.md, .changeset/ready-hoops-ring.md, .changeset/real-turtles-attack.md, .changeset/pre.json	Four changeset entries added documenting patch and minor version bumps covering package updates, TypeScript migration to v6 and tsdown, and export path changes. Pre-release configuration file added specifying next tag with initial version 0.3.1 and four changeset IDs.
Changelog CHANGELOG.md	Extended with unreleased entries for versions 0.4.0-next.3 through 0.4.0-next.0 documenting minor and patch changes corresponding to the new changesets.
Package Configuration package.json	Version bumped to 0.4.0-next.3, module entry changed from .js to .mjs and types from .d.ts to .d.mts, build script switched from tsup to tsdown, and dev dependencies updated including TypeScript (5.9.3 → 6.0.2), eslint, vitest, and related tooling packages.
Build Configuration tsdown.config.ts	Build tool migrated from tsup to tsdown, added target: false configuration option.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A hop through versions, files aligned,
From tsup to tsdown, a tool redesigned,
TypeScript Six now joins the fold,
ESM exports, a story retold,
Release next.3, our bunny heart's gold! 🎉

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title accurately summarizes the main changes: migration to TypeScript 6 and tsdown are the primary focus of the changeset, reflected in dependency updates, build tool changes, and configuration modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ts6-tsdown

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[coderabbitai]

🧹 Nitpick comments (1)

package.json (1)

13-20: Consider adding CJS type declaration path for dual-package consumers.

The main field points to ./dist/index.cjs but the top-level types field only references .d.mts. Since tsdown is configured to generate both .d.mts (ESM) and .d.cts (CJS) declaration files, using conditional types in exports would ensure older tooling and explicit require() consumers correctly resolve the appropriate type definitions.

Consider restructuring exports to use conditional types:

💡 Suggested enhancement

   "exports": {
     ".": {
-      "types": "./dist/index.d.mts",
       "require": "./dist/index.cjs",
-      "import": "./dist/index.mjs"
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
+      }
     },

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@package.json` around lines 13 - 20, The package currently exposes "main":
"./dist/index.cjs" and a top-level "types": "./dist/index.d.mts" but lacks
conditional type paths for CJS consumers; update package.json exports/types so
require() consumers get the CJS declaration and ESM importers get the MTS
declaration: keep "main" and "module" as-is, change the top-level "types" to
point to the CJS declaration (e.g., "./dist/index.d.cts") and add a conditional
"types" mapping inside "exports" for "." with "require": "./dist/index.d.cts"
and "import": "./dist/index.d.mts" (matching the existing "require"/"import" JS
entries) so tooling and require() consumers resolve proper .d.cts vs .d.mts
files.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@package.json`:
- Around line 13-20: The package currently exposes "main": "./dist/index.cjs"
and a top-level "types": "./dist/index.d.mts" but lacks conditional type paths
for CJS consumers; update package.json exports/types so require() consumers get
the CJS declaration and ESM importers get the MTS declaration: keep "main" and
"module" as-is, change the top-level "types" to point to the CJS declaration
(e.g., "./dist/index.d.cts") and add a conditional "types" mapping inside
"exports" for "." with "require": "./dist/index.d.cts" and "import":
"./dist/index.d.mts" (matching the existing "require"/"import" JS entries) so
tooling and require() consumers resolve proper .d.cts vs .d.mts files.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 961eec20-671b-492c-88f5-c389fb5663f2

📥 Commits

Reviewing files that changed from the base of the PR and between a18a53f and c209bb1.

⛔ Files ignored due to path filters (1)

• pnpm-lock.yaml is excluded by !**/pnpm-lock.yaml

📒 Files selected for processing (8)

• .changeset/brave-yaks-argue.md
• .changeset/cozy-swans-add.md
• .changeset/pre.json
• .changeset/ready-hoops-ring.md
• .changeset/real-turtles-attack.md
• CHANGELOG.md
• package.json
• tsdown.config.ts