Question

I am quite new to coffeescript and I am wondering if any more experienced users could point suggest a refactoring for the following code:

splitCollection: =>
  maxLength = Math.ceil(@collection.length / 3)

  sets = Math.ceil(@collection.length / maxLength)
  start = 0    

  for x in [1..sets]   
    if x != sets
      @render new BusinessUnits(@collection.models.slice(start, (maxLength + start)))
    else
      @render new BusinessUnits(@collection.models.slice(start, (@collection.length)))
    start+= maxLength

There does not appear to be a while loop in coffeescript which seems to suggest a better mechanism.

Any suggestions appreciated.

Answer 1

Looks like you are using Backbone.js, which includes Underscore.js, which has the groupBy function.

You could create a “bucketNumber” function:

bucketNumber = (value, index) ->
    Math.floor( index / @collection.length * 3 )

Then group your collection:

sets = @collection.groupBy bucketNumber

Now, assuming ten items, sets should look something like this:

{0: [{}, {}, {}], 1: [{}, {}, {}], 2: [{}, {}, {}, {}]}

From here, it becomes rather straight-forward

for bucketNumber, bucket of sets
    @render new BusinessUnits( bucket )

Here is a jsFiddle showing it in action