Nextjs Landing Pages - TypeScript Error When Checking For Non-Page Types

I am changing the sanity-template-nextjs-landing-pages over to TypeScript.
One of the issues that I cannot resolve in my

[[…slug]].tsx

file is this:
When checking for non-page types with

if(!data?._type === 'page')

, I get a TS error

This condition will always return 'false' since the types 'boolean' and 'string' have no overlap.

The value of

_type

is always a string and I’m pretty sure

!foo === 'bar'

is the right syntax?
What’s the issue and how do I resolve it?

Hi , wonderful that you’re doing that 🙂 I hope you will share the final code with us all!
I will have a look at the issue and get back at you

Until Sanity v3 is closer to an RC (with better TypeScript support), I’m just focusing on the NextJS part of that project.

So you don’t need feedback on this now?

Because I got some TS answers for you :cool_doge:

if (data?._type !== 'page')

:chefs-kiss:
It was a bug in the original code and in ts it would always return

false

because

!data

casts the string to a

boolean

, and

bool === string

will never be true. Removing the

!

will make it so it compares

string

with

string.

Such a simple solution. I never thought of

!==

. That is a simple option and something I could have attempted but never thought of! Thanks so much !

Our amazing team thought of it... 🙌 And pleasure 🙃