Node.js cron runner. Interval is set using moment.js add() function. Check sample code

runCron.js

/*

Sample usage: 

runCron({promise: screenshotsCache, intervalNumber: 5, intervalString: 'minutes'});

This will call "screenshotsCache" Promise every 5 minutes. 
If promise resolves after 6 minutes, it will be called again immediately because 5 mins already passed.

*/

const moment = require('moment');

export default function runCron({promise, intervalNumber, intervalString}) {
  console.log('--- START CRON ---');
  let start = moment();
  let end = null;
  let nextAt = null;

  const checkIfRunAgainAlready = () => {
    if (moment().isSameOrAfter(nextAt)) {
      return runCron({promise, intervalNumber, intervalString});
    } else {
      setTimeout(() => {
        checkIfRunAgainAlready();
      }, 1000);
    }
  };

  const afterEnd = () => {
    if (end === null) {
      end = moment();
      console.log(`~~~~ CRON DONE IN ${end.diff(start)} ms. ~~~~`);
      checkIfRunAgainAlready();
    }
    if (nextAt === null) {
      nextAt = start.add(intervalNumber, intervalString);
    }
  };

  promise()
    .then(() => {
      afterEnd();
    })
    .catch((e) => {
      console.error('#skdlfks CRON error: ', e);
      afterEnd();
    });

}