Updated docs for getServerSideProps and getStaticProps return values

[chozzz]

This fixes the documentation for getServerSideProps and getStaticProps which mislead the defined type.

Current screenshot taken from nextjs doc

However, the declared type for these types are using union type which represents any of the following instead of optional.

Declared types;
GetStaticPropsResult

GetServerSidePropsResult

---

This PR updates the documentation for their return values;

Before: The ... function should return an object with the following optional properties:
After: The ... function should return object with any one of the following properties:

---

Bug

• Related issues linked using fixes #number
• Integration tests added
• Errors have helpful link attached, see contributing.md

Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• Related issues linked using fixes #number
• Integration tests added
• Documentation added
• Telemetry added. In case of a feature if it's used or not.
• Errors have helpful link attached, see contributing.md

Documentation / Examples

• Make sure the linting passes by running yarn lint

[leerob]

Would you mind updating getStaticPaths as well? Thank you!

https://github.com/vercel/next.js/blob/canary/docs/api-reference/data-fetching/get-static-paths.md#getstaticpaths-return-values

[chozzz]

Would you mind updating getStaticPaths as well? Thank you!

https://github.com/vercel/next.js/blob/canary/docs/api-reference/data-fetching/get-static-paths.md#getstaticpaths-return-values

@leerob getStaticPaths seems to be already in order based on its type. Can you elaborate more?

[leerob]

It says "following required properties:" which I feel is misleading. "Any of the following" seems to make more sense, because there are multiple types of fallback - what do you think?

[chozzz]

It says "following required properties:" which I feel is misleading. "Any of the following" seems to make more sense, because there are multiple types of fallback - what do you think?

I think the following required properties is the correct one.
getStaticProps object need both paths and fallback as per the declared type

[balazsorban44]

Left a comment on getStaticProps.

To clarify getStaticPaths, paths is always required, but fallback is optional and will default to fallback: false

I was wrong, both are actually required, you were right, so the getStaticPaths docs looks good.

next.js/packages/next/build/utils.ts

Lines 694 to 704 in 0fb1183

	if (
	!(
	typeof staticPathsResult.fallback === 'boolean' ||
	staticPathsResult.fallback === 'blocking'
	)
	) {
	throw new Error(
	`The \`fallback\` key must be returned from getStaticPaths in ${page}.\n` +
	expectedReturnVal
	)
	}

[chozzz]

@balazsorban44 Updated the wording on getStaticProps, please re-review.