@hanzo/cal-atoms

Hanzo-owned fork of Cal.com's scheduling components — the Booker, CalProvider, availability, and related UI. Used under Cal.com's MIT grant (see NOTICE).

This is a vendored prebuilt distribution: the JavaScript, types, and styles are shipped as-is. There is no build step. Consumers get the components plus globals.min.css.

import { Booker, CalProvider } from "@hanzo/cal-atoms";
import "@hanzo/cal-atoms/globals.min.css";

In this repo the SPA never imports this package directly — it imports @hanzo/cal, the thin Hanzo booking surface. This package is the foundation @hanzo/cal builds on.

Why a fork (two upstream defects fixed here)

1. dayjs extends were tree-shaken. Upstream ships "sideEffects": false, so a bundler is free to drop the vendored dayjs.extend(utc); dayjs.extend(timezone); … side-effect. Once dropped, dayjs.tz is undefined and the Booker crashes at bootstrap on dayjs.tz.guess(). Fixed by declaring the dayjs vendor modules side-effectful:

   "sideEffects": ["**/vendor/dayjs/**", "**/vendor/timezone-constants.js"]

2. The atoms need zustand 4, not 5. These atoms were built and tested against zustand 4 (upstream's own devDependency pins 4.5.2), but the peer range ^4.0.0 || ^5.0.0 lets a package manager install zustand 5. Under zustand 5 the Booker breaks two ways: its useSyncExternalStore semantics changed, so the stores infinite-loop (Maximum update depth exceeded / "getSnapshot should be cached"); and zustand 5 demoted use-sync-external-store to an optional peer, so the zustand/traditional selector shim goes missing and useSyncExternalStoreWithSelector resolves to undefined (... is not a function). zustand 4 carries that shim as a regular dependency and matches the atoms' selector code, so the fork narrows the peer to ^4.0.0. Pin zustand 4.5.2 to match exactly what upstream tested.

These fixes live in the package metadata, not in a downstream patch — any consumer's bundler gets correct behavior with no extra configuration.

Maintenance runbook (tracking upstream)

The vendored bytes track @calcom/atoms@<version>. To advance to a new upstream:

# 1. Fetch the pristine upstream package.
npm pack @calcom/atoms@<new-version>
tar -xzf calcom-atoms-<new-version>.tgz            # -> package/

# 2. Replace the vendored files (everything except our own manifest/NOTICE/README).
rsync -a --delete \
  --exclude package.json --exclude README.md --exclude NOTICE \
  package/ packages/cal-atoms/

# 3. Bump "version" in packages/cal-atoms/package.json to the new upstream
#    version, keeping the two fixes above (sideEffects + use-sync-external-store).
#    Re-diff the upstream package.json for any new dependencies/exports to mirror.

# 4. Rebuild and verify the artifact gates (see repo LLM.md). The prod bundle is
#    minified, so grep the assignment form, not a `function <name>` declaration:
pnpm build
#    grep -c '\.extend('                       <bundle>   # ~14 (dayjs plugins preserved, not 3)
#    grep -c 'useSyncExternalStoreWithSelector=function' <bundle>   # >0 (selector shim present)

# 5. Publish (patch/minor/major per the upstream change).
cd packages/cal-atoms && npm publish

Never re-introduce a pnpm patch on the upstream package: the whole point of this fork is that the fix is owned here, in one place.