#MoonBit Cron

#Features

• Parses the five fields: minute, hour, day of month, month, and day of week.
• Supports *, individual values, ranges (a-b), lists (a,b), and steps (*/n, a-b/n).
• Accepts standard uppercase month names (JAN through DEC) and weekday names (SUN through SAT) in their corresponding fields.
• Validates empty fields, malformed list items, non-positive steps, bounds, and oversized numeric input before it can overflow.
• Uses standard Cron day-of-month/day-of-week OR semantics when both fields are restricted.
• Calculates the next matching minute across month and leap-year boundaries.
• Runs on the wasm, wasm-gc, JavaScript, and native MoonBit targets.

#Install

moon add lijunjie860/moonbit_cron

git clone https://github.com/lijunjie860/MoonBit-Cron.git
cd MoonBit-Cron
moon check --target all --warn-list +73 --deny-warn
moon test --target all --warn-list +73 --deny-warn
moon run cmd/main

#API example

import {
  "lijunjie860/moonbit_cron" @cron,
}

fn next_workday_trigger() -> Result[@cron.Time, String] {
  let expression = @cron.parse("*/15 9-17 * * 1-5")
  match expression {
    Err(message) => Err(message)
    Ok(expr) => expr.next(@cron.Time::{
      year: 2026,
      month: 10,
      day: 15,
      hour: 9,
      minute: 7,
      weekday: 4,
    })
  }
}

#Runnable CLI demonstration

moon run cmd/main

Expression: */15 9-17 * * 1-5
Matches now: false
Next trigger: 2026-10-15 9:15 (weekday 4)

#Validation

moon fmt --check
moon check --target all --warn-list +73 --deny-warn
moon build --target all --warn-list +73 --deny-warn
moon test --target all --warn-list +73 --deny-warn
moon info

#License