This worked for me -
cron.schedule("*/10 * * * * *", function() {
console.log("running a task every 10 second");
});
Hope this helps someone.
Reference - https://support.acquia.com/hc/en-us/articles/360004224494-Cron-time-string-format
var cron = require('node-cron');
cron.schedule("0 */10 * * * *", async () => { //every 10 minutes
console.log("running a task every 10 minutes");
});