[added] url parameter rules

[itajaja]

Closes #2286

Another pull request for custom matching parameter rules, this time with the specifics proposed by @th0r

This time was easier, and I like the final result more. I still need to add the documentation and the rule inheritance feature, but let men know what you think for now

[itajaja]

I added the nesting as well. I don't know how much is useful though, as @taion said, you want to put the rule on the same component the parameter is declared, for readability, but it wasn't hard to implement so I put it. Let me know what you think, I am working on updating the doc in the meantime.

[taion]

Haven't had a chance to look at this yet, but should we close #2402?

[itajaja]

@taion If we all agree on this syntax, I would say so :)

[taion]

I think in a vacuum I'd have preferred the Flask-style syntax for specifying URL variables (wrapped in angle brackets rather than prefixed with a colon - but probably still with the external type specification), but given what we already have, this is better.

[taion]

You can just use ES6 object spread stuff to write this as

route.params = {...parentRoute.params, ...route.params}

[taion]

I haven't had time to look at this in depth, but I really think the right way to do this architecturally per @mjackson's comment is to split out something with an API that looks like matchPattern into a separate library.

[itajaja]

You mean like a separate repo right? So we aim at refactoring out RouteUtils, with caching and all? Before embarking in that, I want to make sure we are in-line. suggestions (naming, scope, etc.) are welcome

[taion]

You mean PatternUtils, right? That's my thought - pattern-matching is not React Router specific.

[itajaja]

whops, patternUtils. Let's see what I am able to do.

[taion]

I'm closing this PR for now since the development is in a separate repo.