Typing issue in react.tsx: 'flagsmith' is possibly 'null' about flagsmith-js-client

[matthewelwell]

Hi @davinov thanks for this. I think that the link you included is pointing to a different line of code than the one you mentioned in the fix?

I'm not overly familiar with the JS client so I'm waiting for one of our other engineers to respond, but I'd be interested to know if there is a particular scenario you have identified where flagsmith is not set? I would imagine this to always be set. Perhaps it's a typing issue further down the line for example? Should useContext ever not return a valid instance of flagsmith?

[davinov]

Thanks for your quick reply

You're right about the line, my mistake!
The same condition is repeated twice in this file:

• once in FlagsmithProvider L41: this seems OK because there the flagsmith argument is of type IFlagsmith, and not optional
• once in useFlagsmithLoading L114, which gets flagsmith from the context useContext(FlagsmithContext). In that case, it seems that it could be null because of the intiialization value of the context (export const FlagsmithContext = createContext<IFlagsmith<string,string> | null>(null)

So another possibility would be to change the initialization value to a "default" flagsmith instance. However, that instance would not have any of important the parameters expected to be set by the consumers of the package, such as api or environmentID, so I guess this second option seems less appropriate to me.

I'll try to make a minimal reproduction repo this evening if I can spare some time.

[davinov]

When creating a new repo, I've noticed that my import of flagsmith/react was mistaked. My IDE imported automatically flagsmith/src/react instead 🤦
That included your source code to our typechecking, instead of relying on the exposed types (the .d.ts files).

You may still want to fix the error that raises when developing your client though, if you got some time :)

Thanks again for the quick reply, and sorry for the noise