React JS check whether strict mode is enabled

Question

Is there any way to know whether the strict mode is enabled in React?

useEffect(() => {

  if(strictModeEnabled) {}

})

I didn't find any information in the docs.

Answer 1

You can use this

export const useEffectOnce = ( effect )=> {

  const destroyFunc = useRef();
  const effectCalled = useRef(false);
  const renderAfterCalled = useRef(false);
  const [val, setVal] = useState(0);

  if (effectCalled.current) {
      renderAfterCalled.current = true;
  }

  useEffect( ()=> {

      // only execute the effect first time around
      if (!effectCalled.current) { 
        destroyFunc.current = effect();
        effectCalled.current = true;
      }

      // this forces one render after the effect is run
      setVal(val => val + 1);

      return ()=> {
        // if the comp didn't render since the useEffect was called,
        // we know it's the dummy React cycle
        if (!renderAfterCalled.current) { return; }
        if (destroyFunc.current) { destroyFunc.current(); }
      };
  }, []);
};

call it by

useEffectOnce( ()=> {
    console.log('my effect is running');
    return () => console.log('my effect is destroying');
});

Read more here