Ruby/Rails using || to determine value, using an empty string instead of a nil value

Question

I usually do

 value = input || \"default\"

so if input = nil

 value = \"default\"

But how can I do this so in

Answer 1

Maybe irrelavant but I would use highline like this:

require "highline/import"

input = ask('Input: ') { |q| q.default = "default" }

It works without Rails. Really neat solution.

Answer 2

Rails adds presence method to all object that does exactly what you want

input = ''
value = input.presence || "default"
=> "default"

input = 'value'
value = input.presence || "default"
=> "value"

input = nil
value = input.presence || "default"
=> "default"

Answer 3

I usually do in this way:

value = input.blank? ? "default" : input

In response to the case that input might not be defined, you may guard it by:

value = input || (input.blank? ? "default" : input)
# I just tried that the parentheses are required, or else its return is incorrect

For pure ruby (not depending on Rails), you may use empty? like this:

value = input || (input.empty? ? "default" : input)

or like this (thanks @substantial for providing this):

value = (input ||= "").empty? ? "default" : input