dsh-cron-parse

Cron expressions are the lingua franca of scheduled jobs, yet a string of stars, slashes, and comma-separated lists can be hard to interpret at a glance. dsh-cron-parse turns that manual mental exercise into a single structured call: hand it an expression and get back a validation verdict, a human-readable Chinese description, the expanded value of each of the five fields, and up to ten concrete upcoming run timestamps — no more hunting through man pages or writing ad-hoc parsers.

Parsing follows classic Vixie semantics: when both dayOfMonth and dayOfWeek are constrained the match is an OR union; when only one is constrained it drives the schedule; when neither is constrained the job fires every day. Supported syntax includes wildcards, step ranges, closed intervals, multi-value lists, and case-insensitive month/day names. The engine also pre-checks unsatisfiable combinations such as 'February 30' and returns an early error instead of iterating pointlessly. All calculations advance in the requested IANA timezone and emit ISO 8601 timestamps with explicit offsets, so cross-timezone scheduling stops being a guess.

It is a good fit for product teams building job dashboards that need to tell end users exactly when a task will next run, and for ops or full-stack engineers who want to translate a raw cron string into plain language inside CI logs, alerting rules, or internal tooling. Zero dependencies, pure ESM, no build step — drop it in and call it.