NestJS | node-cron

nestjs-node-cron is a NestJS module that provides a simple and intuitive API for scheduling tasks using cron expressions. It is built on top of the popular node-cron library. This package offers a service to manage cron tasks easily within a NestJS application.

Installation

To install the package, use npm or yarn:

npm install nestjs-node-cron 
or
yarn add nestjs-node-cron

Getting Started

NodeCronModule

First, you need to import the NodeCronModule into your NestJS module.

import { Module } from '@nestjs/common';
import { NodeCronModule } from 'nestjs-node-cron';

@Module({
  imports: [NodeCronModule],
})
export class AppModule {}`

NodeCronService

Inject the NodeCronService into your service or controller where you want to manage cron tasks.

import { Injectable } from  '@nestjs/common'; 
import { NodeCronService } from  'nestjs-node-cron'; 

@Injectable() 
export  class  CronService { 
	constructor(private readonly nodeCronService: NodeCronService) {}
	setupCronJobs() { 
		// Example usage 
	} 
}

API Documentation

Methods

Validate(expression: string): boolean

Validates whether the provided string is a valid cron expression.

Parameters:

• expression: A string representing the cron expression to validate.

Returns:

• boolean: true if the expression is valid, false otherwise.

Usage:

const isValid = this.nodeCronService.Validate('*/5 * * * *');
console.log(isValid); // Output: true

Schedule(expression: string, func: ((now: Date | "manual" | "init") => void) | string, options?: ScheduleOptions)

Schedules a new task to execute the given function according to the cron expression.

Parameters:

• expression: A string representing the cron expression for the schedule.
• func: A function to execute when the cron expression ticks. It can be a function or a string command.
• options?: Optional scheduling options as defined by node-cron.

Returns:

• ScheduledTask: The scheduled task instance.

Usage:

this.nodeCronService.Schedule('*/5 * * * *', () => {
  console.log('Running a task every 5 minutes');
});

this.nodeCronService.Schedule('0 0 * * *', 'echo "Midnight task"');

GetTasks()

Retrieves the list of tasks created using the schedule function.

Returns:

• Map<string, ScheduledTask>: A map of task identifiers to scheduled task instances.

Usage:

const tasks = this.nodeCronService.GetTasks();
tasks.forEach((task, id) => {
  console.log(`Task ID: ${id}, Task: ${task}`);
});

Example Usage

Here's a complete example of how to use NodeCronService in a NestJS service:

import { Injectable } from '@nestjs/common';
import { NodeCronService } from 'nestjs-node-cron';

@Injectable()
export class Service {
  constructor(private readonly nodeCronService: NodeCronService) {
    this.setupCronJobs();
  }

  setupCronJobs() {
    // Schedule a task to run every minute
    this.nodeCronService.Schedule('* * * * *', () => {
      console.log('Task running every minute');
    });

    // Validate a cron expression
    const isValid = this.nodeCronService.Validate('0 0 * * *');
    console.log('Cron expression is valid:', isValid);

    // Get all scheduled tasks
    const tasks = this.nodeCronService.GetTasks();
    console.log('Scheduled tasks:', tasks);
  }
}

Credits

This package is built on top of the node-cron library. Thanks to the authors and contributors of node-cron for providing a robust cron scheduling solution for Node.js.

For more information, check out our GitHub repository