# System map — date-fns/date-fns

> Canonical page: https://codevetter.com/unpack/date-fns/system-map

# System map — date-fns/date-fns

Scanned commit 717ce0a807ea4c6b540d015b5c408723175b2838 (2026-09-22). Generated by codevetter codevetter 1.15.0 on 2026-10-02.

Source inspection; upstream code and tests were not executed.

The repository separates date calculation, date subclasses, documentation publishing, and development tooling into workspace packages. Consumers enter through exported functions and classes rather than a central application startup routine. Core package output supports both ESM and CommonJS, while workspace exports reference source files. Persistent storage appears in the documentation publisher; the inspected calculation paths operate on in-memory dates and options.
- pnpm-workspace.yaml includes pkgs/* and the time-zone engine-test package; root TypeScript references core, docs, utc, tz, and engine tests. — [pnpm-workspace.yaml#L1-L3](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pnpm-workspace.yaml#L1-L3) [tsconfig.json#L1-L10](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/tsconfig.json#L1-L10)
- The core export surface includes independent arithmetic, difference, interval, formatting, parsing, predicate, and boundary functions, plus shared types. — [pkgs/core/src/index.ts#L3-L51](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/src/index.ts#L3-L51) [pkgs/core/src/index.ts#L180-L248](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/src/index.ts#L180-L248)
- Published core root imports resolve to index.js/index.d.ts, while require resolves to index.cjs/index.d.cts. — [pkgs/core/package.json#L763-L775](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/package.json#L763-L775)
- TZDate extends TZDateMini's target-zone representation; UTCDate extends UTCDateMini's redirected UTC accessors. — [pkgs/tz/src/date/index.js#L1-L18](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/tz/src/date/index.js#L1-L18) [pkgs/tz/src/date/mini.js#L3-L28](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/tz/src/date/mini.js#L3-L28) [pkgs/utc/src/date/mini.js#L22-L29](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/utc/src/date/mini.js#L22-L29) [pkgs/utc/src/date/index.js#L3-L16](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/utc/src/date/index.js#L3-L16)
- The private dev package exposes date-fns-build-package and date-fns-test-tz; its builder preserves modules, externalizes imports, and rewrites relative import extensions. — [pkgs/dev/package.json#L1-L12](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/dev/package.json#L1-L12) [pkgs/dev/src/build/package.ts#L16-L32](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/dev/src/build/package.ts#L16-L32) [pkgs/dev/src/build/package.ts#L74-L89](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/dev/src/build/package.ts#L74-L89)
- The docs package exposes date-fns-docs and uses Firebase Admin with Typesaurus collections named packages, versions, and pages. — [pkgs/docs/package.json#L18-L19](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/docs/package.json#L18-L19) [pkgs/docs/package.json#L41-L46](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/docs/package.json#L41-L46) [pkgs/docs/src/db.ts#L1-L10](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/docs/src/db.ts#L1-L10) [pkgs/docs/src/bin.ts#L21-L30](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/docs/src/bin.ts#L21-L30)
- Auxiliary applications are a React/Vite formatted-date example and a Hono playground serving browser JavaScript on port 3000. — [pkgs/core/examples/vite/src/main.tsx#L1-L10](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/examples/vite/src/main.tsx#L1-L10) [pkgs/core/examples/vite/src/App.tsx#L4-L12](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/examples/vite/src/App.tsx#L4-L12) [pkgs/core/examples/vite/vite.config.ts#L1-L7](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/examples/vite/vite.config.ts#L1-L7) [pkgs/tz/playground/src/server.ts#L5-L20](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/tz/playground/src/server.ts#L5-L20)
- Temporal-oriented index.tp.ts implementations have a separate Vitest project and are excluded from production source-entry discovery and declaration output. — [pkgs/core/src/addMonths/index.tp.ts#L1-L18](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/src/addMonths/index.tp.ts#L1-L18) [pkgs/core/vitest.config.ts#L28-L45](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/vitest.config.ts#L28-L45) [pkgs/dev/src/build/package.ts#L60-L70](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/dev/src/build/package.ts#L60-L70) [pkgs/core/tsconfig.dist.json#L19-L23](https://github.com/date-fns/date-fns/blob/717ce0a807ea4c6b540d015b5c408723175b2838/pkgs/core/tsconfig.dist.json#L19-L23)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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