How to convert a ruby hash object to JSON?
require 'json/ext' # to use the C based extension instead of json/pure
puts {hash: 123}.to_json
One of the numerous niceties of Ruby is the possibility to extend existing classes with your own methods. That's called "class reopening" or monkey-patching (the meaning of the latter can vary, though).
So, take a look here:
car = {:make => "bmw", :year => "2003"}
# => {:make=>"bmw", :year=>"2003"}
car.to_json
# NoMethodError: undefined method `to_json' for {:make=>"bmw", :year=>"2003"}:Hash
# from (irb):11
# from /usr/bin/irb:12:in `<main>'
require 'json'
# => true
car.to_json
# => "{"make":"bmw","year":"2003"}"
As you can see, requiring json
has magically brought method to_json
to our Hash
.