I’m experiencing unexpected behavior with state updates and useEffect in my Next.js application. I have a component with a lock/unlock functionality, but the state updates and side effects are not occurring as I expect them to. Here’s the relevant code:

const [isLocked, setIsLocked] = useState(false);

useEffect(() => {
  if (isLocked && index === -1) {
    console.log("Inside use-effect");
    // Logic to change some other state variable
  }
}, [StateVariable#2, isLocked]);

const handleLockClick = () => {
  console.log(isLocked);
  if (!isLocked) {
    setStateVariable#2(true);
    setIsLocked(true);

    // Some other logic

    console.log(isLocked);
    console.log("Clicked!");
  }
  else {
    setStateVariable#2(false);
    setIsLocked(false);
  }
};

When I click the button that triggers handleLockClick, I get the following console output:

First click:

false
false
Clicked!

Second click:

false
false
Clicked!
Inside use-effect

Third click:

true

I expected isLocked to become true after the first click, but it remains false for the first two clicks. The useEffect only runs after the second click, and isLocked only shows as true on the third click.

Questions:

1. Why isn’t isLocked updating to true on the first click?
2. Why does the useEffect only run after the second click?
3. How can I modify my code to make the state update and useEffect run as expected on the first click?

I’ve tried using the functional form of setState, but the issue persists:

const handleLockClick = () => {
  setIsLocked(prevIsLocked => {
    console.log(prevIsLocked);
    if (!prevIsLocked) {
      setStateVariable#2(true);
      // Other logic...
      console.log("Clicked!");
      return true;
    } else {
      setStateVariable#2(false);
      return false;
    }
  });
};

Any insights into what might be causing this behavior and how to resolve it would be greatly appreciated. Thank you!