.from problem with react

[robmr.dev]

Hello! How are you? I have a problem with the use of .from animation, i kind of new on programing.
i did use the .to with not much problems, but i cannot make it works with the .from as it seems its not as the other one.
i'm trying to the the text to show up from the bottom of the screen! it showed up one as i was refreshing the page, but never again. what i'm doing wrong? 

Thanks you So much!!
 

See the Pen XWoNLvV by robmrdev (@robmrdev) on CodePen

[GSAP Helper]

Hi @robmr.dev and welcome to the GreenSock forums!

 

Perhaps the problem is that React 18 runs in "strict" mode locally by default which causes your useEffect() to get called TWICE! Very annoying. It has caused a lot of headaches for a lot of people outside the GSAP community too.

 

.from() tweens use the CURRENT value as the destination and it renders immediately the value you set in the tween, so when it's called the first time it'd work great but if you call it twice, it ends up animating from the from value (no animation). It's not a GSAP bug - it's a logic thing.

 

For example, let's say el.x is 0 and you do this: 

useEffect(() => {
  // what happens if this gets called twice?
  gsap.from(el, {x: 100})
}, []);

 

The first time makes el.x jump immediately to 100 and start animating backwards toward the current value which is 0 (so 100 --> 0). But the second time, it would jump to 100 (same) and animate back to the current value which is now 100 (100 --> 100)!  See the issue?

 

In GSAP 3.11, we introduced a new gsap.context() feature that solves all of this for you. All you need to do is wrap your code in a context call, and then return a cleanup function that reverts things: 

// typically it's best to useLayoutEffect() instead of useEffect() to have React render the initial state properly from the very start.
useLayoutEffect(() => {
  let ctx = gsap.context(() => {
    // all your GSAP animation code here
  });
  return () => ctx.revert(); // <- cleanup!
}, []);

 

One of the React team members chimed in here if you'd like more background.

 

We strongly recommend reading the React article at

 

 

We have a series of starter templates using GSAP in React apps so you can take a look:

https://stackblitz.com/@GreenSockLearning/collections/gsap-react-starters

 

Happy tweening!

[robmr.dev]

Wooo!! Thanks you So much! it solved all the issues! this way i can keep doing all i need!

I'll read the article you send!

Good day!