fix: add guards for common Next.js App Router mistakes

[stipsan]

Common mistakes such as this:

function getPosts(): Promise<Post[]> {
  const client = createClient({})
  return client.fetch<Post[]>('*[_type == "post"]', {cache: 'no-store'})
}

will now throw an error:

Type 'unknown' is not assignable to type 'Promise<Post[]>'.ts(2322)

Hovering over fetch, which renders with a strikethrough, gives more context:

These checks only happen at compile time, in TypeScript, there are no errors or logs happening at runtime to avoid risking introducing a breaking change.

There are two options for resolving the TS error.

a) Move the argument to the third parameter

-  return client.fetch<Post[]>('*[_type == "post"]', {cache: 'no-store'})
+  return client.fetch<Post[]>('*[_type == "post"]', {}, {cache: 'no-store'})

b) Add a query params generic that allows the param

-  return client.fetch<Post[]>('*[_type == "post"]', {cache: 'no-store'})
+  return client.fetch<Post[], {cache: string}>('*[_type == "post"]', {cache: 'no-store'})

[socket-security]

New dependencies detected. Learn more about Socket for GitHub ↗︎

Package	New capabilities	Transitives	Size	Publisher
npm/next@14.1.0	environment, filesystem, network, shell, unsafe	+27	1.12 GB	vercel-release-bot

View full report↗︎