Hover effects with GSAP

Basic hover

const button = document.querySelector("button")!;

const tween = gsap.to("button", {
  scale: 2,
  duration: 1,
  x: 200,
  paused: true,
});

button.addEventListener("mouseenter", () => {
  tween.play();
});

button.addEventListener("mouseleave", () => {
  tween.reverse();
});

There are three steps to creating hover animations with GSAP:

1. Create your tween or timeline in an initial paused state
2. Add an event listener for the mouseenter event, and play the animation with the play() method
3. Add an event listener for the mouseleave event, and reverse the animation with the reverse() method

Scale effects

When doing animations with scale, we need to keep in mind that scaling up an element will make it pixelated, so we need to make a few optimizations to take care of that issue:

• Use the willChange css property for better performance
• Make sure to scale up to the original size. Initially scale down the element, and then scale it back up with scale(1), back to the original size to avoid pixelation.
• Set the transformOrigin to the center of the element, so that it scales from the center.

willChange

The willChange css property allows for optimizations with performance by telling the browser that the selected elements will be animated, so prepare for it.

This helps avoid things like text jitters.

.element {
  will-change: transform;
  transition: ; //..
}

Remove flash of unstyled content

In your css, set the visibility of the elements you want to animate to be hidden. And then toggle back the visibility to visible in your javascript.

.element {
  visibility: hidden;
}

YOu could also set the autoAlpha property in your GSAP tweens, which toggles the visibility back to visible and sets the starting opacity.

• autoAlpha: 0 : sets visibility: visible and animates opacity from 0 to 1

gsap.timeline(".element", {
  autoAlpha: 0,
  // ...
});