docs: document req.params changes in 5.x

[krzysdz]

Fixes #2090

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[krzysdz]

Just one thing that I remembered - req.params has null prototype, unless the path is a regular expression. With regexes req.params is a normal object (see regexpMatcher in router)

[bjohansebas]

Thanks @krzysdz!

What do you think about changing it to this suggestion, which includes more information and code examples showing what changed, to make the change easier to understand?

[krzysdz]

Your suggestion is definitely clearer. I'll admit that I'm not great at writing documentation.

There is just the question about prototype that may or may not be null... I did not notice it initially and forgot to update the PR when I tested some more things and realised that regular expressions have req.params with a regular Object prototype. To be fair this inconsistency is probably something that should be changed in router.

[bjohansebas]

There is just the question about prototype that may or may not be null... I did not notice it initially and forgot to update the PR when I tested some more things and realised that regular expressions have req.params with a regular Object prototype. To be fair this inconsistency is probably something that should be changed in router.

yep, when it's not regexp then the object is created here, whereas here is where the object is created, probably we should change that in the router so both ways are the same

[bjohansebas]

LGTM!