Add Clerk Express SDK docs

[EmmanouelaPothitou]

Create documentation for the Express SDK and a guide for migrating from the Node SDK to Express SDK

Important

🔎 Previews:

• Quickstart
• Overview
• Migration guide

[alexisintech]

please tag me to fully review once all the content is verified as correct by the other reviewers !

[alexisintech]

What is requireAuth ? We don't have this documented anywhere, but you mentioned that it's exported by the Express SDK @dimkl

[dimkl]

@alexisintech it's a new export that's only included in the @clerk/express package (Express SDK). This PR is meant to document it.
code ref for requireAuth(): https://github.com/clerk/javascript/blob/main/packages/express/src/requireAuth.ts

[jescalan]

Excited for this new package to land! Dropped a bunch of feedback on the docs 🙇‍♂️

[jescalan]

I think maybe putting this under upgrade guides might make more sense

[dimkl]

Aren't upgrade guides meant to be related to major Clerk upgrades? I think that we should keep it here since it's specific to the Clerk express package and how you can use it if you are already using the @clerk/clerk-sdk-node package.

[github-actions]

Hey, here’s your docs preview: https://clerk.com/docs/pr/1201

[jescalan]

It's getting closer here!

:P

[dimkl]

Aren't upgrade guides meant to be related to major Clerk upgrades? I think that we should keep it here since it's specific to the Clerk express package and how you can use it if you are already using the @clerk/clerk-sdk-node package.

[jescalan]

@dimkl

Aren't upgrade guides meant to be related to major Clerk upgrades? I think that we should keep it here since it's specific to the Clerk express package and how you can use it if you are already using the @clerk/clerk-sdk-node package.

This is a major upgrade imo. We're deprecating the sdk-node package, and anyone using the sdk-node package needs to migrate over to a completely different package that is massively breaking. I think this is the appropriate place for such a guide.

[wobsoriano]

Heads up 🫡 I will do another update of this PR based on the updates on this PR. I'll let you know when it's ready, again!

[wobsoriano]

Ready for another round of review 🫡 Updated it with the refactored middlewares

[jescalan]

I think this is good! Let's do it.