Update caching.mdx

[maral]

What?

Fix misleading information in the docs about mixing cached and uncached fetch calls during dynamic rendering.

Why?

I followed the guide (using Next.js 15.3.2) and tried it out with this code:

  const joke = await fetch("https://api.chucknorris.io/jokes/random", {
    cache: "no-cache",
  });
  const jokeData = await joke.json();

  console.log("Fetched joke:", jokeData.value);

  const joke2 = await fetch(
    "https://api.chucknorris.io/jokes/random?category=dev"
  );
  const jokeData2 = await joke2.json();
  console.log("Fetched joke2:", jokeData2.value);

After building and starting the production server, when I refresh the page, both jokeData.value and jokeData2.value are different, uncached. If I want the other fetch to be cached, I need to explicitly enable caching, e.g.

  const joke = await fetch("https://api.chucknorris.io/jokes/random", {
    cache: "no-cache",
  });
  const jokeData = await joke.json();

  console.log("Fetched joke:", jokeData.value);

  const joke2 = await fetch(
    "https://api.chucknorris.io/jokes/random?category=dev",
    {
      cache: "force-cache",
    }
  );
  const jokeData2 = await joke2.json();
  console.log("Fetched joke2:", jokeData2.value);

This way the first fetch is not cached while the second one is.

How?

The previous version claimed:

Other fetch requests that do not opt out of caching will still be cached in the Data Cache.

But below in the guide, we can see this:

The default caching behavior of fetch (e.g., when the cache option is not specified) is equal to setting the cache option to no-store:

So the first citation is misleading - the fetch requests are not cached by default (with dynamic rendering - static rendering would cache the single call it into the output), so we actually need to explicitly enable caching to have them cached.

[ijjk]

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[ijjk]

Allow CI Workflow Run

• approve CI run for commit: d7724dc

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[icyJoseph]

Hi,

Thanks for the contribution.

That's correct, when the default caching behavior of fetch changed - a few places in the docs got outdated.