Welcome! Today I will focus on notifications in JavaScript. Let’s go!

Notifications in JavaScript

I want my pomodoro timer to run in the background - I decided my website will be one of many pinned tabs in my Chrome. But this statement makes some complications - how do I know that my pomodoro ends? How do I tick if this 25 minutes was good or bad? I need a way to tell a user that it is time for a break. For this task, I will use notifications.

JavaScript notification standard says that:

A notification is an abstract representation of something that happened, such as the delivery of a message.

Cool! Exactly what I need - let’s jump into the code.

How I implemented notifications

At first, you have to ask a user for permission to display notifications:

let notificationPermission = false;

Notification.requestPermission().then((result) => {
  if (result === 'granted') {
    notificationPermission = true;
  }
});

At the beginning I setup variable that will be a flag for my code to know if user grants permission to display notifications. This is done below. Notification.requestPermission() returns promise so I call then and if result is granted I set a flag variable to be true.

I want my notifications to be displayed when my time ends:

function displayNotification() {
  if (!notificationPermission) return;
  const notification = new Notification("Time's up!", {
    icon: 'stopwatch.png',
  });

  notification.addEventListener('click', () => {
    window.focus();
  });
}

function timer(seconds) {
  // rest of the code

  if (secondsLeft < 0) {
    // rest of the if
    displayNotification();
  }
}

In displayNotification I check if user granted permission to see notification, if not the function terminates. Then I create new notification with stopwatch icon and Time's up! text. notification can have event listener attached to click event so I did that so when user clicks notification it will switch him/ her to pomodoro timer tab.

This is how my notification looks like:

What next?

That’s all for today blog post! Feel free to comment. The next thing I want to tackle is 5 and 15 min breaks between pomodoros.

Repo with this code is available on github.

References

• Using the Notifications API

Special thanks to Kasia for being an editor for this post. Thank you.

Written by Krzysztof Żuraw who lives and works in Wrocław. About page.