Checking promise is missing from 02.extra-2.js

[epicweb-dev]

Checking promise is missing from 02.extra-2.js

[kentcdodds]

Hi @chumanfu,

The nice part of the change we've made is that now instead of expecting people to call run with undefined, we just expect them to not call run at all if they don't want to trigger state changes. So that's what we do:

  React.useEffect(() => {
    if (!pokemonName) {
      return
    }
    run(fetchPokemon(pokemonName))
  }, [pokemonName, run])

We only call run if we have a pokemonName to fetch.

I hope that makes sense :)

[chumanfu]

Thanks for your reply. I still don't see how 02.extra02.js means that we don't need to check the promise since in 02.js we checked both pokemon and the promise.
Could there still not be a situation where fetchPokemon could not return a valid promise?

[kentcdodds]

If you dive into the implementation of fetchPokemon, you'll see that it always returns a promise. If run were typed with TypeScript, it would require that the value it receives is a Promise and then you'd get static type checking that you're always passing a promise.