Last Updated: February 25, 2016
·
1.278K
· francpaul

CoffeeScript empty switch

Sometimes a switch is useful, but one or more of the switch conditions are not straight forward to setup.

Here's the default documented switch behaviour:

go = (activity) ->
  alert(activity)

bingoDay = "Sat"

day = 'Tue'

switch day
  when "Mon" then go 'work'
  when "Tue" then go 'relax'
  when "Thu" then go 'iceFishing'
  when "Fri", "Sat"
    if day is bingoDay
      go 'bingo'
      go 'dancing'
  when "Sun" then go 'church'
  else go 'work'

Here's a contrived empty switch version.
Notice that we can use any truth condition to switch.

day = "Sat"

switch
  when 5 is 7
    go 'this can never run'
  when day is "Mon" then go 'work'
  when day is "Tue" then go 'relax'
  when day is "Thu" then go 'iceFishing'
  when day is "Sun" then go 'church'
  when bingoDay is day
     go 'bingo'
  when day is "Wed"
    go 'work'
  else go 'dancing'

Because sometimes a switch is just more elegant than a if - else if - else