replaces use of indexOf with more idomatic CoffeeScript

[schliffer]

Removes all use of Array.prototype.indexOf to support IE8

[schliffer]

@adambiggs

[aeischeid]

Is your main goal to get support for IE<9 or to make Spine more clear/consistent?

I find indexOf to be more clear than using 'in', but that may just be a personal preference. What do others think?

As for the IE<9 thing. My general stance is if there are shims that deal with that easily enough then I don't want to let deprecated browser implementations influence the library any more than they have to.

[schliffer]

I'm trying to accomplish both. I think using in is far more clear than indexOf for situations where you do not need the index for some other reason. For cases where you need the index to then remove the item from the list using splice, I think the Coffee list comprehension is just as clear and probably more idiomatic. And I definitely think that

if ev in evts
  evts = (e for e in evts when e isnt ev)

is more clear than

if ~(i = evts.indexOf(ev))
  evts.splice(i, 1)

There is no real reason to use ~ combined with indexOf when in is available.

The change to list.coffee is probably uglier but that change is more about IE8 than about clarity.

[adambiggs]

@aeischeid Personally i think in is more clear & concise.

@jschliffer can you commit the JS as well please.

Interesting, looks like indexOf is quite a bit slower than simply finding the index using a loop.

[aeischeid]

if ~(i = evts.indexOf(ev)) is definitely a bit odd, but evts = (e for e in evts when e isnt ev) is a lot more to digest than evts.splice(i, 1)

Oh well, I can go with the flow here. It is pretty interesting that looping is faster. That would have been my next minor objection, that index of is probably faster, but that is the opposite of what I expected. Given that I'll just spin it for myself that we are doing this for a performance improvement ;)

[jamiter]

Just a detail, but shouldn't this loop use a break?

for item, idx in @items
  index = idx if item is @current

Like:

for item, idx in @items when item is @current
  index = idx
  break

Just a little performance thingy ;)

[adambiggs]

Yes it should! Nice catch :)