Support multiple functions in app.param

[tanqhnguyen]

#2603

A simple change but it might be useful in some cases where we can write shorter code to reuse middleware in app.param

[dougwilson]

Don't use req.params as a bag-o-things.

[dougwilson]

[key].concat(fns) will inadvertinately allow for the arguments to be arrays, because it'll flatten in certain cases, i.e.:

$ node -pe '[2].concat([1,2])'
[ 2, 1, 2 ]

[tanqhnguyen]

I think that is how apply works. I mean we need an array for apply to work

[dougwilson]

I'm talking about concat; you need to use something else that won't flatten the fns array.

[dougwilson]

Actually, nvm, I didn't look all the way, sorry!

[tanqhnguyen]

No problem. (Not related) Is my new test case alright?

[dougwilson]

(Not related) Is my new test case alright?

Yep

[tanqhnguyen]

@dougwilson Is this one still valid?

[jonchurch]

From what I can tell, app.param is being removed from Express in v5, so unless there are still plans to land this in 4.x, this PR can likely be closed.

[dougwilson]

So app.param is not being removed in 5.0. In fact, it is being updated to include Promise support.

[jonchurch]

Ahh thank you @dougwilson, I see now that this commit was reverted by this later commit.