[Bug] - TypeError: Cannot read properties of null (reading 'getValue')

[joelpierre]

Currently seeing the below, I think there may be some guard clauses missing before calling "getValue"

TypeError: Cannot read properties of null (reading 'getValue')
    at /var/task/node_modules/.pnpm/flagsmith@3.19.1/node_modules/flagsmith/react.js:1:1616
    at Array.map (<anonymous>)
    at c (/var/task/node_modules/.pnpm/flagsmith@3.19.1/node_modules/flagsmith/react.js:1:1581)
    at e.useFlags (/var/task/node_modules/.pnpm/flagsmith@3.19.1/node_modules/flagsmith/react.js:1:2458)

[novakzaballa]

Hi @joelpierre, can you please provide more details and context about this issue, including how can we reproduce it?

[joelpierre]

Hey, it turns out it was very bespoke to our setup with server side Algolia not playing ball, however it would be great if in your SDK the useFlag hook didn't do this

const res = useMemo(() => {
        const res: any = {}
    flags.map((k) => {
        res[k] = {
                enabled: flagsmith!.hasFeature(k), // <------  non-null assertion
                value: flagsmith!.getValue(k), // <------  non-null assertion
        }
    }).concat(traits?.map((v) => {
        res[v] = flagsmith!.getTrait(v) // <------  non-null assertion
    }))

As you can see the flagsmith! which is what is blowing up for us. Not sure if you can change these to flagsmith?. ...

[kyle-ssg]

Hey again, I think maybe we could, however I'm not sure what cases would exist where the Flagsmith Providers don't get a Flagsmith instance. Was there a good example that I'm maybe not understanding?

[joelpierre]

With Algolia SSR they want you to do some pretty weird and wonderful things for server side rendering as you can see here: https://www.algolia.com/doc/guides/building-search-ui/going-further/server-side-rendering/react/#with-nextjs and as a result we have to pre-render the Algolia listing "stuff" server side and renderToString... in essence all our _app providers are not loaded in this serverState until hydration kicks in on the client.

It would be good if flagsmith didn't blow up though haha as I went down a rabit hole debugging it 😬 . OR if there was more of a check to ensure the provider state was set before trying to do anything further?

[novakzaballa]

Hi there, could you please include a sample minimal project failing, and a clear description of what would be the expected behavior?