Difference between Fetch API and Next.js clients

[ZilvinasAbr]

Hi, was looking a bit into source code of both fetch client and next client and the differences seemed to be quite "cosmetic". I was wondering if that is the case or there is something more that is happening with Next.js's client of hey-api?

[mrlubos]

Hey @ZilvinasAbr, from Next.js documentation:

Next.js extends the Web fetch() API to allow each request on the server to set its own persistent caching and revalidation semantics.

That's the main difference and thing people were complaining about not working with the Fetch client. In terms of how this translates into clients, the Next.js client has a slightly different interceptor signature and we don't pass request around, only options. And it supports the Next.js features of course.

[ZilvinasAbr]

I'll try to test it out if it works as expected, I expected it should work because Typescript was auto-suggesting the Next.js options

[mrlubos]

The actual implementation shouldn't work because of using Request, I'm pretty sure that's what others said

[ZilvinasAbr]

Maybe it is the case for when using the client in client side, not server-side?

[mrlubos]

Why are you asking? Did your tests indicate that?

[ZilvinasAbr]

Well, actually when trying to use Next.js v14.2.25 I've found that the default caching of fetch GET requests were not working neither with client-fetch lib (^0.3.4) nor next fetch. For Next.js v15, that is not the case: by default GET requests shouldn't get cached. Haven't tried to play around with custom cache or revalidate options