How does onUpdate get triggered even I have no start or end values defined ?

[Sougata]

gsap.to(img, {
  repeat: -1, // Infinite loop
  onUpdate: () => {
    angle += step; // Increment the angle
    let x = radius + radius * Math.cos(angle);  
    let y = radius + radius * Math.sin(angle);  
    gsap.set(img, { left: x, top: y }); // Update the position
  },
});

here is  my code

[GSAP Helper]

Without a minimal demo, it's very difficult to troubleshoot; the issue could be caused by CSS, markup, a third party library, a 3rd party script, etc. Would you please provide a very simple CodePen or Stackblitz that illustrates the issue? 

 

Please don't include your whole project. Just some colored <div> elements and the GSAP code is best. See if you can recreate the issue with as few dependencies as possible. Start minimal and then incrementally add code bit by bit until it breaks. Usually people solve their own issues during this process! If not, at least we have a reduced test case which greatly increases your chances of getting a relevant answer.

 

See the Pen aYYOdN by GreenSock (@GreenSock) on CodePen.

that loads all the plugins. Just click "fork" at the bottom right and make your minimal demo: 

 

Using a framework/library like React, Vue, Next, etc.? 

CodePen isn't always ideal for these tools, so here are some Stackblitz starter templates that you can fork and import the gsap-trial NPM package for using any of the bonus plugins: 

• React (please read this article!)
• Next
• Svelte
• Sveltekit
• Vue
• Nuxt

 

Please share the StackBlitz link directly to the file in question (where you've put the GSAP code) so we don't need to hunt through all the files. 

 

Once we see an isolated demo, we'll do our best to jump in and help with your GSAP-specific questions. ✅

[mvaneijgen]

I'm not sure what your code should do, below my inperperatikon, but you're missing some values in your code. Be sure to always include a demo with your question, so that we can take a look at your code in action.

 

See the Pen qEWYOaG?editors=1111 by mvaneijgen (@mvaneijgen) on CodePen.

 

Quote

even I have no start or end 

What do yo mean with this? If you do nothing your tween will just play, by default a tween has a duration of 0.5 seconds, which means if you set repeat: -1, it will play every 0.5 over and over again. 

 

Hope it helps and happy tweening!