Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript Callback Functions in JavaScript Callbacks with Timers Using Anonymous Functions with setInterval

Posted by jlampstack
jlampstack
23,932 Points

Another Approach using IIFE

Andrew Chalkley : You mentioned that anonymous functions are not suitable for our clock application but how about using IIFE? It seems to work perfectly fine.

// Render time to screen (IIFE)
(() => {
  // Immediately displays time
  clockSection.textContent = getTime();
  // Updates clock at intervals of 1 second
  setInterval( () => {
    clockSection.textContent = getTime();
  }, 1000);
})();

1 Answer

Steven Parker
Steven Parker
229,644 Points
Steven Parker
Steven Parker
229,644 Points

The IIFE isn't necessary, you can just do this:

// immediately display time
clockSection.textContent = getTime();
// then update clock at intervals of 1 second
setInterval( () => {
    clockSection.textContent = getTime();
  }, 1000);

But the issue (with or without IIFE) is that we violate the "DRY" principle by replicating the code that used to be in the "tickClock" function. In this particular case, it's only one line so the replication isn't a big deal; but in a more complex application it might be.