Fixes #16864 

The `router` can be missing in a test environment when trying to render a `Link` component. This PR bails out of `router.prefetch()` when `router` is missing.

The alternative is for users to mock `next/link` or to mock the `router` and wrap their test components.

Please let me know any feedback.

Fixes #20403

This updates the error shown when a path doesn't match the dynamic route in `getStaticPaths` to not include the `locale` since this isn't considered when matching against the dynamic route. 

This ensures rewrites to API routes with i18n enabled handles as an API route correctly. This also adds tests for API routes in the i18n test suite

Fixes: https://github.com/vercel/next.js/issues/20725

Fix mini typo

Docs for https://github.com/vercel/next.js/pull/20216/.

This is a follow-up to https://github.com/vercel/next.js/pull/20596 and https://github.com/vercel/next.js/pull/20658 ensuring the `as` value is prefixed with the `basePath` correctly with a query. This updates the test to also ensure no errors are shown when a query is present on the index `basePath` route. 

Fixes: https://github.com/vercel/next.js/pull/20757#issuecomment-754338510

* Updated deploy button URL

* Update bottom button

You can initialize the Firebase app instance without checking for window, but it is required for using the analytics module.

This is a #19325 reconfigured to support a loader passed in via a `loader` prop on the Image component, rather than using a config-based approach.

The idea is that applications wanting to use a custom loader will create a wrapper element for the  image component that incorporates that loader. See a simple example of this pattern in the integration tests. 

This solution is similar to the one prototyped by @ricokahler in #20213 and described at https://github.com/vercel/next.js/issues/18606#issuecomment-720149156

---

Closes #19325
Fixes #18606

Co-authored-by: NKanta Kodama <kanta.kodama@linecorp.com>

## summary
- Explicitly define return types
- Add type of  [Observer](https://github.com/vercel/next.js/pull/20728/files#diff-5de64b97b2f26e4e41d197a8295e8750825c75b8ca557a4b947a4c3569345974R7)

Closes: https://github.com/vercel/next.js/issues/20197

`getLoginSession` takes only one argument

Adds the `pr` section from https://docs.microsoft.com/en-us/azure/devops/pipelines/repos/github?view=azure-devops&tabs=yaml#pr-triggers to filter paths that don't require test runs on PRs. 

Currently pages with `notFound: false` from `getServerSideProps` behave the same as `notFound: true`, i.e. just having the key is enough to result in a 404. This fixes the check in render.tsx and adds tests for it.

Adds an example using `lru-cache` to implement a simple rate limiter for API routes ([Serverless Functions](https://vercel.com/docs/serverless-functions/introduction)).

**Demo: https://nextjs-rate-limit.vercel.app/**

Closes https://github.com/vercel/next.js/issues/19481

The current text implies `query` is a string. IMO it would be better if it clarified that `query` is an object containing the query string's keys and values

Edit:
Relevant docs url: https://nextjs.org/docs/basic-features/data-fetching#getserversideprops-server-side-rendering

https://ant.design/docs/react/getting-started#Import-on-Demand
At the document, We don't need to use `babel-import-plugin` to `Import on Demand`.

Hi, 

I'm submitting this PR for consideration as a new example app showing Styled JSX with SCSS working inside and outside storybook with example components.

Only known issue: I noticed that when running this example with:

`$ yarn next ./examples/with-storybook-styled-jsx-scss`

I receive the following error:

```
error - ./pages/_app.js
Error: [BABEL] .../next.js/examples/with-storybook-styled-jsx-scss/pages/_app.js: Cannot find module 'styled-jsx-plugin-sass' (While processing: ".../next.js/node_modules/next/babel.js")
```

However I notice that this same missing module error is triggered when running this existing example app "with-styled-jsx-scss".

Any changes/tweaks needed?

Thanks!

I made the following changes.

- Addition of procedure for setting private_key
- Addition of procedure for creating a database and setting database_url

This pull request correctly assigns boolean attributes for `<script />` to match the element as it is created by a server-side render.

Prior to this pull request, we'd double-execute `<script>` tags with the `async`, `defer`, or `nomodule` property.

---

Fixes #9070

As with `const width`, it should be declared just before it is used.

**What's the problem this PR addresses?**

`@next/mdx` adds the webpack loader `@mdx-js/loader` without resolving it to an absolute path

Depends on https://github.com/vercel/next.js/pull/17606

**How did you fix it?**

`require.resolve` the webpack loader before adding it