The custom RRULE panel covers most patterns but can't express "every
weekday at 9, 12, and 18" or "every 15 minutes within working hours"
in a single rule. RRULE's BYxxx fields can technically combine, but
the picker UX gets unwieldy fast. Cron expressions cover everything
in one line.
Storage / dispatch
- Cron rules live in the same `reminders.rrule` column with a sentinel
prefix: `CRON:0 9 * * 1-5`. No schema change.
- `@cmbot/shared` now exports:
CRON_PREFIX, isCronRule, stripCronPrefix, validateCronExpression
- `nextOccurrence(rule, tz, after)` and `validateMinInterval(rule, tz)`
detect the prefix and dispatch to `cron-parser`; non-cron rules
continue to flow through rrule unchanged.
- `cron-parser@^5.5.0` added as an explicit dep on @cmbot/shared
(it was already transitively present via pg-boss).
Server actions
- `createReminderAction` / `updateReminderAction`: when rrule has the
CRON: prefix, the user's date+time inputs are ignored — the action
validates the cron, runs the min-interval check (5 min between
fires), and computes scheduledAt as the next match of the cron
expression after now. The bot's existing fire-reminder loop
re-arms via `nextOccurrence` after each fire, which already speaks
cron via the dispatch above.
Picker
- New "Cron expression…" preset at the bottom of the radio list:
"Full sec/min/hour/day/month/dow combinational power"
Selecting it reveals a CronPanel:
* font-mono cron input (5- or 6-field accepted)
* inline examples: 0 9 * * 1-5, */15 * * * *, 0 9,12,18 * * *,
0 0 1 * *
* note that the Date+Time controls above are ignored once a cron
expression is set
- RecurrenceSpec gains an optional `cron` string and a new `kind: "cron"`.
- buildRrule emits `CRON:<expr>` for cron specs.
- specFromRrule round-trips a CRON-prefixed rule back into the spec.
- describeRecurrence renders "Cron: <expr>" so the list view and
review steps show the expression.
Tests (+10; 17 shared + 26 bot + 138 web = 181 total)
- packages/shared rrule.test.ts (+8):
* CRON_PREFIX / isCronRule / stripCronPrefix
* nextOccurrence on a CRON rule returns the right next match in the
operator timezone (e.g. weekday 9 AM KL ↔ exact UTC instant)
* RRULE rules still flow through unchanged
* validateMinInterval on cron: hourly OK, every-minute rejected,
malformed string returns a useful error
* validateCronExpression positive + negative cases
- recurrence.test.ts (+5): cron preset round-trip, label assertions,
`buildRrule`/`specFromRrule` for cron specs.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
yiekheng
5f1897daa5