CoffeeScript Object.merge

merge.coffee

merge = (xs...) ->
  if xs?.length > 0
    tap {}, (m) -> m[k] = v for k, v of x for x in xs

tap = (o, fn) -> fn(o); o

console.log merge {foo: '1', bar: 'baz'}, {bar: 'bis'} , {wombat: 'fishpaste'}

###
{ foo: '1', bar: 'bis', wombat: 'fishpaste' }
###

Thanks, very neat. And works, unlike the CoffeeScript helper method displayed here http://coffeescript.org/documentation/docs/helpers.html
Which is strange, since its part of the compiler... hmmm

Nice, I can make it even more neat:

merge=(xs... ->
  if xs?.length>0
    tap {},(m)->m[k]=v for k,v of x for x in xs
tap=(o, fn)->fn(o);o

But thanks anyway.

This is really handy - thanks. Could you explain line 5? I didn't know semi-colon was allowed in coffeescript....

@alexbfree Semicolons are fully optional in CS. (console.log "hi" and console.log "hi"; are both 100% valid), but they are still the only way to fit multiple statements on the same line.

To quote the coffeescript website directly:
"You don’t need to use semicolons ; to terminate expressions, ending the line will do just as well (although semicolons can still be used to fit multiple expressions onto a single line)." (source)

The version by @bogdan (23 Nov 2015) unfortunately doesn't compile for me. The original version works fine, though.