Hi everyone,
it's a silly question (and I'm kind of ashamed to ask it), but I frequently
must do things like that:
a.present? ? a : b
or a real world example:
params[:user][:name].present? ? params[:user][:name] : "default name"
I think these are perfect cases to use a "coalesce" method. Something like:
# a.coalesce(b)
params[:user][:name].coalesce("default name")
or on a non-OOP/non-chained syntax:
# coalesce(a, b, c, ...)
coalesce(params[:user][:name], "default name")
This method saves me a lot of time, so I create it in virtually every
project that I have:
# application.rb
class Object
def coalesce(arg)
self.blank? ? arg : self
end
end
Ex.:
2.coalesce(1)
=> 2
nil.coalesce(1)
=> 1
The complete version that I use is that:
class Object
def coalesce(obj, *args)
args.unshift(obj) # "obj" is to force at least 1 argument
args.unshift(self) if self.class != Object # non-chained use
result = args.shift
args.each do |arg|
if result.blank?
result = arg
else
break
end
end
result
end
alias_method :clsc, :coalesce
end
This complete version allows me to use with all these syntax:
coalesce(1, 2)
coalesce(1, 2, 3)
1.coalesce(2)
1.coalesce(2, 3)
clsc(1, 2)
My question is: there is a native "coalesce" method (or something similar)
in Ruby or Rails? I'm afraid to reinventing the wheel.
PS: a || b is not a valid answer because "" || "x" returns "" (and the main
use for this is with strings).
Thanks,
Daniel Loureiro
http://www.learnwithdaniel.com
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