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Eraze86

timeline reverse wont work. gets "Cannot read properties of null"

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    const tl = gsap.timeline()
    useEffect(() => {

        if (isOpen) {
            tl.to([toggle.current], { height: "18rem", ease: "none" })
            tl.to([link.current], { delay: 0.2, opacity: 1 })
        }else{
           console.log("close") 
      
        } 
    }, [isOpen, tl])

im trying to make my menu open och close in the same way. 
but at soon as i put any code more then console.log in the else {} it gives me  "Cannot read properties of null"
i dont understand why? 
ive tryed tl.reverse and  writing tl.to code but it always gives me the same error. 

i have also tryed if else, and if(!isOpen) but gives me the same

Any input? 

 

the first code works when i press the button to open the meny, 

i can change it aswell so it only works when i close the button. 

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It's pretty tough to troubleshoot without a minimal demo - the issue could be caused by CSS, markup, a third party library, your browser, an external script that's totally unrelated to GSAP, etc. Would you please provide a very simple CodePen or CodeSandbox that demonstrates the issue? 

 

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

 

Here's a starter CodePen that loads all the plugins. Just click "fork" at the bottom right and make your minimal demo

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

 

If you're using something like React/Next/Nuxt/Gatsby or some other framework, you may find CodeSandbox easier to use. 

 

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

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thank you so mush för the help. But when  i try any of thos alternatives i get tl.current error, is undefinde. 

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Hi,

 

Be sure to create your timeline in a useEffect hook with an empty dependencies array and store it in a ref with the useRef hook:

const tl = useRef();
useEffect(() => {
  tl.current = gsap.timeline()
  	// add your instances to the timeline
}, []);

If you're actually doing that and you're getting the same error you should check that the instance actually exists first in your useEffect hook:

const tl = useRef();
useEffect(() => {
  tl.current = gsap.timeline()
  	// add your instances to the timeline
}, []);

useEffect(() => {
  tl.current && tl.current.reversed(!isOpen);
}, [isOpen]);

If you keep having issues, please update your codesandbox so we can take a look at what could be the problem, right now I'm just guessing what the issue might be.

 

Finally please check the React guide in order to see how to implement and run GSAP animations in a React app:

 

Happy Tweening!

 

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