@cronuru/convert

Zero-dependency cron expression conversion and validation across every major scheduler dialect — Unix, Quartz, Kubernetes, AWS EventBridge, Spring, and GitHub Actions.

Powers the converter at cronuru.com.

npm i @cronuru/convert

Why

The same schedule is written differently on every platform. Day-of-week is 0–6 (Sun=0) on Unix but 1–7 (Sun=1) on Quartz and EventBridge; Quartz and EventBridge require the ? placeholder; some dialects add a seconds or year field; L/W/# only exist on a few. @cronuru/convert normalizes a source expression and re-emits it in the target dialect's exact shape — and tells you when a conversion loses precision or hits a platform limit.

No runtime dependencies. ESM + CJS. Typed.

Usage

import { convert, convertToAll, validate } from "@cronuru/convert";

convert("0 9 * * 1", "unix", "quartz");
// { ok: true, expression: "0 0 9 ? * 2", warnings: [], target: "quartz" }

// Day-of-week is renumbered (Mon: 1 → 2) and day-of-month becomes "?"
// because Quartz requires exactly one of the two day fields to be "?".

convertToAll("*/15 * * * *", "unix");
// { unix, quartz, kubernetes, eventbridge, spring, "github-actions" }
// each → { ok, expression, warnings, target }

validate("0 9 1 * 1", "unix");
// { ok: true, findings: [{ severity: "warning",
//   title: "Day-of-month AND day-of-week both set", ... }], fieldCount: 5 }

Conversions surface non-fatal warnings (precision loss, the DOM/DOW OR-trap, GitHub Actions' 5-minute floor, unsupported special characters), and ok is false only when the source can't be parsed at all.

CLI

npx @cronuru/convert "0 9 * * 1" --from unix --to quartz
# 0 0 9 ? * 2

npx @cronuru/convert "*/15 * * * *" --from unix --to all
# unix            */15 * * * *
# quartz          0 */15 * * * ?
# kubernetes      */15 * * * *
# eventbridge     */15 * * * ? *
# spring          0 */15 * * * *
# github-actions  */15 * * * *

API

| Export | Signature | |---|---| | convert | (expr, from, to) => ConversionResult | | convertToAll | (expr, from) => Record<DialectSlug, ConversionResult> | | validate | (expr, dialect) => ValidationResult | | DIALECTS / DIALECT_LIST / getDialect | dialect metadata |

DialectSlug is one of: unix, quartz, kubernetes, eventbridge, spring, github-actions.

Dialects

| Dialect | Fields | Seconds | Year | Day-of-week | ? | |---|---|---|---|---|---| | Unix cron | 5 | – | – | 0–6 (Sun=0) | – | | Quartz | 6–7 | ✓ | ✓ | 1–7 (Sun=1) | required | | Kubernetes | 5 | – | – | 0–6 (Sun=0) | – | | AWS EventBridge | 6 | – | ✓ | 1–7 (Sun=1) | required | | Spring @Scheduled | 6 | ✓ | – | 0–7 | – | | GitHub Actions | 5 | – | – | 0–6 (Sun=0) | – |

See the full per-dialect references at cronuru.com/dialects.

License

MIT © Cronuru