Switch 'non-else' case? - coffeescript

Question

Is it possible to get rid of useless ok variable in this code?
cond1 = true
cond2 = true
cond3 = true
switch
when !cond1
console.log "cond1 failed"
when !cond2
console.log "cond2 failed"
when !cond3
console.log "cond3 failed"
else
ok = true
if !ok then process.exit(1)
console.log "good"

Answer 1

You may change your code to
cond1 = true
cond2 = true
cond3 = true
switch
when !cond1
console.log "cond1 failed"
when !cond2
console.log "cond2 failed"
when !cond3
console.log "cond3 failed"
process.exit(1) if !(cond1 && cond2 && cond3)
console.log "good"
with the disadvantage of duplicating the condition checking.
I guess that you want to show all unmet conditions (because you put the process.exit call after the switch statement). If so, your code has the problem that it does only shows the first unfulfilled condition. So I would just use if statements
cond1 = false
cond2 = false
cond3 = true
if !cond1
console.log "cond1 failed"
if !cond2
console.log "cond2 failed"
if !cond3
console.log "cond3 failed"
process.exit(1) if !(cond1 && cond2 && cond3)
console.log "good"
All over all you'll have to decide if the double checking of your conditions or one setting and checking of a variable is more expensive in comparison with the readability of your code.
I would give readability a higher priority if not realy dealing with performance or memory problems an use something like:
cond1 = false
cond2 = false
cond3 = true
error={"success":true,"msg":"good"}
addError=(msg)->
error.msg="" if error.success
error.success=false
error.msg+=msg+"\n"
checkForErrors=(e)->
console.log e.msg
if !e.success
process.exit(1)
addError "cond1 failed" if !cond1
addError "cond2 failed" if !cond2
addError "cond3 failed" if !cond3
checkForErrors error
If you should write the condition checking before or after the addError call depends of the length of your condition code.