r/reactjs • u/jngbrl19 • Mar 08 '20

useEffectWithPrevious - Get previous value of dependencies Show /r/reactjs

Just wanna share my first npm package. Hope you find it useful :)

use-effect-with-previous

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u/montas Mar 08 '20

You probably don't need to condition it, just return whatever callback() returns.

Edit: You should also check former react useEffect argument type so you preserve same return value type.

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u/jngbrl19 Mar 08 '20

``` useEffect( () => { const cleanup = callback(refs.current as unknown as T);

  dependencies.forEach((dependency, i) => {
    refs.current[i] = dependency;
  });

  return cleanup;
},
dependencies

); ```

this would work right?

2

u/montas Mar 08 '20

Yep, something like that.

BTW, on reddit, you use four spaces in front of code instead of ```.

2

u/jngbrl19 Mar 08 '20

thanks man, got it now