Simple Cron Job Scheduler

A simple cron job scheduler for Node.js built with EventEmitter. This library allows you to schedule tasks based on cron expressions, manage retries, and control job execution in an easy-to-use manner.

Features

• Cron Expression Parsing: Parse cron expressions in the format second minute hour day month dayOfWeek.
• Job Scheduling: Schedule jobs to run based on cron expressions.
• Job Execution: Execute tasks with error handling and retries.
• Event-driven: Emit events when the scheduler starts, stops, or when jobs run, succeed, or fail.
• Retry Mechanism: Retry failed jobs a defined number of times with a configurable delay.
• Single and Recurring Jobs: Support for jobs that run once or recur.

Installation

npm install node-cron-js

Usage

Importing the module

const cron = require('node-cron-js');

Scheduling a Job

const jobId = cron.schedule('*/5 * * * * *', async () => {
  console.log('Job executed');
});

Stopping a Job

cron.stop(jobId);

Listing All Jobs

const jobs = cron.listJobs();
console.log(jobs);

Stopping All Jobs

cron.stopAll();

General Usage

const cron = require("node-cron-js");

// Define a job that runs every 10 seconds
const jobId = cron.schedule("*/10 * * * * *", async () => {
  console.log("Task is running...");
}, {
  maxRetries: 3,
  retryDelay: 5000,
});

// Listen for events
cron.on("job_failed", ({ jobId, error, attempt }) => {
  console.log(`⚠️ Job ${jobId.toString()} failed on attempt ${attempt}: ${error.message}`);
});

cron.on("job_retried", ({ jobId, attempt }) => {
  console.log(`🔄 Retrying job ${jobId.toString()} (attempt ${attempt})...`);
});

Events

cron emits the following events:

• scheduler_started: Emitted when the scheduler starts.
• scheduler_stopped: Emitted when the scheduler stops.
• job_scheduled: Emitted when a job is scheduled.
• job_started: Emitted when a job starts executing.
• job_finished: Emitted when a job finishes successfully.
• job_failed: Emitted when a job fails.
• job_retried: Emitted when a job is retried.
• job_max_retries_reached: Emitted when a job has reached the maximum retry limit.
• job_stopped: Emitted when a job is stopped manually.
• all_jobs_stopped: Emitted when all jobs are stopped.

LICENSE

MIT License

Copyright (c) 2025 [Oghenekparobo Onosemuode]

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