perf: bundle size optimizations (sideEffects, #private mangling, minify tuning)

[DaSchTour]

Summary

Three bundle-size optimizations, no public API or behavior changes:

1. sideEffects field — the package had none, so bundlers couldn't tree-shake any of it. Only src/index.ts and src/wrappers/react.ts have real import-time side effects (customElements.define), so only their dist counterparts are marked side-effectful. Consumers who only import from keksmeister/core, keksmeister/adapters/*, or keksmeister/i18n/* can now be tree-shaken by bundlers that respect this field.
2. Native #private fields — TypeScript private members compile to plain public properties, so their names survive minification untouched. Converted internal-only members in src/core/*.ts and src/ui/*.ts to native #private fields/methods, which both esbuild (vite's build) and terser can safely rename to single letters since they're lexically private, never string-keyed. ConsentManager#store and #subjectId were kept as regular TS private because consent-manager.test.ts reaches into them via bracket notation (manager['store']); native private fields don't support that.
3. Terser tuning — added pure_getters=true to the compress pass (small, safe win — all getters in the codebase are pure reads).

Tested and rejected (documented so it isn't retried)

• --ecma 2022: byte-identical output.
• passes=2: byte-identical once combined with pure_getters — one pass already reaches the fixed point.
• --mangle-props regex=/^#/: byte-identical to plain --mangle. Terser already renames #-prefixed private class members as part of standard name mangling (verified empirically), so no extra flag is needed.
• vite.config.ts → build.cssMinify: 'lightningcss': byte-for-byte identical output to esbuild's default CSS minifier for the ?inline-imported banner/trigger CSS. Added the dependency, measured, then reverted (bun remove lightningcss) since it added a dependency for zero benefit.

Size table (raw / gzip)

File	Before		After		Δ gzip
	raw	gzip	raw	gzip
dist/keksmeister.js	38,894 B	10,781 B	36,041 B	10,316 B	−465 B (−4.3%)
dist/keksmeister.min.js	33,646 B	9,964 B	30,752 B	9,536 B	−428 B (−4.3%)
dist/keksmeister.umd.cjs	33,940 B	10,077 B	31,084 B	9,664 B	−413 B (−4.1%)

CI's bundle-size gate (dist/keksmeister.js, gzip) checks against a 12 kB limit (.github/workflows/ci.yml, not the 10 kB originally assumed) — comfortably passes at 10,316 B (10.07 kB).

Test plan

• bun run typecheck — clean
• bun run test — 112/112 passing
• bun run build — clean, sizes recorded above
• Smoke-tested dist/keksmeister.js and dist/keksmeister.min.js in a happy-dom sandbox: custom elements register, ConsentManager.acceptAll/rejectAll/isAccepted/getChoices work, <keksmeister-banner> renders into its shadow root with the manager wired through the new #private fields.
• Reproduced the CI bundle-size check locally — passes.

🤖 Generated with Claude Code

[codecov]

Bundle Report

Changes will decrease total bundle size by 5.71kB (-7.84%) ⬇️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
keksmeister-Keksmeister-esm	36.04kB	-2.85kB (-7.34%) ⬇️
keksmeister-Keksmeister-umd	31.08kB	-2.86kB (-8.41%) ⬇️

Affected Assets, Files, and Routes:

view changes for bundle: keksmeister-Keksmeister-umd

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
keksmeister.umd.cjs	-2.86kB	31.08kB	-8.41%

Files in keksmeister.umd.cjs:

• ./src/ui/keksmeister-trigger.ts → Total Size: 2.44kB

• ./src/core/consent-logger.ts → Total Size: 4.89kB

• ./src/core/cookie-store.ts → Total Size: 1.92kB

• ./src/core/service-adapter.ts → Total Size: 1.15kB

• ./src/ui/keksmeister-banner.ts → Total Size: 14.57kB

• ./src/core/consent-manager.ts → Total Size: 7.4kB

• ./src/core/script-blocker.ts → Total Size: 3.08kB

view changes for bundle: keksmeister-Keksmeister-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
keksmeister.js	-2.85kB	36.04kB	-7.34%

Files in keksmeister.js:

• ./src/core/service-adapter.ts → Total Size: 1.12kB

• ./src/ui/keksmeister-banner.ts → Total Size: 14.14kB

• ./src/core/script-blocker.ts → Total Size: 2.99kB

• ./src/core/cookie-store.ts → Total Size: 1.86kB

• ./src/ui/keksmeister-trigger.ts → Total Size: 2.37kB

• ./src/core/consent-logger.ts → Total Size: 4.74kB

• ./src/core/consent-manager.ts → Total Size: 7.2kB

[codecov]

Codecov Report

❌ Patch coverage is 72.45763% with 65 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/ui/keksmeister-banner.ts	47.19%	41 Missing and 6 partials ⚠️
src/ui/keksmeister-trigger.ts	0.00%	10 Missing ⚠️
src/core/script-blocker.ts	86.95%	0 Missing and 3 partials ⚠️
src/core/cookie-store.ts	80.00%	1 Missing and 1 partial ⚠️
src/core/service-adapter.ts	88.23%	2 Missing ⚠️
src/core/consent-logger.ts	97.36%	0 Missing and 1 partial ⚠️

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