one time effect with useEffect

[dwhitney]

useEffect doesn't appear to work as a "one time effect". I'd like to use it to send a message to a web worker when a component loads, but nothing happens until the component unmounts. I'd use useAff, but because it sets state, I'm getting into a nasty infinite loop in my particular case. If you need an example, I can put one together, but perhaps I just need clarification on how to do a "one time efect"

Thanks!

[maddie927]

The effect will clean up and rerun any time the provided key changes. Try a constant valve as the key, such as unit. Another option is to construct your effect such that rerunning it isn’t a problem. That isn’t always possible though.

[dwhitney]

ah it does work. It was not clear to me that I was returning the cleanup effect from the function, so everything was wrapped up in that return value. I've made a PR (#8) with some docs clarifying this if anyone else runs into the same issue.

[maddie927]

Ah yeah, everything could be documented better. I’ve been lazy about things that are in the React docs though 😅