How to call a function/notification at specific offset/interval durations in JavaScript?

Question

In my recent project, I came across a situation where I have to send a notifications to client based on specific schedule. For an example: schedule value is 8s,14s,20s then first notification will be send after 8s, next is on 14s and last is on 20s. How can we achieve this functionality?

Answer 1

I would do something like this:

function scheduleNotification(seconds){
  setTimeout(function(){
    // your logic here
    // you could also pass a callback to be executed here
  }, seconds * 1000);
}

function sendNotifications(){
  scheduleNotification(8);
  scheduleNotification(14);
  scheduleNotification(20);
}

sendNotifications();

Answer 2

You can do something like this:

const intervalDuration = [8, 14, 20]; // you can add or delete intervals

for (let i = 0, len = intervalDuration.length; i < len; i++) {
      setTimeout(\* function *\, intervalDuration[i] * 1000);
}

Here, you can add multiple interval based on your requirement. For your use case, setTimeout is the only option as you need to call notifications on different intervals.