feat: optional params and static segments

[lordofthecactus]

Closes: #9550

Allows optional params and optional static segments

Optional params examples

:lang?/about will get expanded matched with

/:lang/about
/about

/multistep/:widget1?/widget2?/widget3?
Will get expanded matched with:

/multistep
/multistep/:widget1
/multistep/:widget1/:widget2
/multistep/:widget1/:widget2/:widget3

Same with static segments

/fr?/about will get expanded and matched with:

/about
/fr/about

Context

Code was added at the point of flattenRoutes

Feedback required

Should we allow intercalated situations? currently:
/one/:two?/three/four? gets matched with:

/one/:two/three
/one/:two/three/:four

[changeset-bot]

🦋 Changeset detected

Latest commit: afbcf9a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
react-router	Minor
@remix-run/router	Minor
react-router-dom	Minor
react-router-dom-v5-compat	Minor
react-router-native	Minor

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Thank you for signing the Contributor License Agreement. Let's get this merged! 🥳

[ryanflorence]

Awesome! Thanks Daniel! Pedro will work with you to get this over the finish line.

[ryanflorence]

I think we should support /one/:two?/three/four?, yes. The concern is always ranking when multiple patterns match the URL. I imagine we handle it the same as if the user typed them all out by hand:

<Route path="/one/:two?/three/four?" />
// becomes
1. <Route path="/one/:two/three/four" />
2. <Route path="/one/three/four" />
3. <Route path="/one/:two/three" />
4. <Route path="/one/three" />

And the ranking should behave the same way.

[brophdawg11]

Agreed - this "exploding" approach (before scoring/ranking) is designed to do just that - behave as if the user manually exploded the enumerations out on their own 👍

[pcattori]

Looks like CI is failing due to filesize limitations. @lordofthecactus , could you bump the 35kB to 35.5kB for packages/router/dist/router.umd.min.js in package.json?

[lordofthecactus]

@pcattori made the changes

[ryanflorence]

We gotta get @developit in here to shrink it all down again.