node-cron

Distributed run coordination — opt-in distributed: true runs a task on a single instance per fire across a fleet (the #477 use case). Ships a built-in NODE_CRON_RUN env-var default (one designated runner, no dependencies) and a pluggable RunCoordinator (via setRunCoordinator, or the per-task runCoordinator option) for high-availability, per-fire coordination (e.g. a Redis lock). Adds the distributedTtl option and an execution:skipped event carrying a reason ('not-elected' | 'coordinator-error'). Works for inline and background tasks. (#549, closes #477)

Task introspection on ScheduledTask: getNextRuns(n) (preview the next N run times), match(date), msToNext(), isBusy(), runsLeft() and getPattern().

cron.parse(expression) and cron.validateDetailed(expression) — decompose an expression into its fields, or get every field-level problem (without throwing) for tooling and richer error messages.

getNextMatch no longer scans every time of day on a day that matches the day-of-month but not the weekday. A dense expression constrained by both (e.g. * * * 15 * 1) could take minutes to resolve; it is now instant.