class Hash
# Returns a new hash with +self+ and +other_hash+ merged recursively.
#
# h1 = { x: { y: [4,5,6] }, z: [7,8,9] }
# h2 = { x: { y: [7,8,9] }, z: 'xyz' }
#
# h1.deep_merge(h2) #=> {:x => {:y => [7, 8, 9]}, :z => "xyz"}
# h2.deep_merge(h1) #=> {:x => {:y => [4, 5, 6]}, :z => [7, 8, 9]}
# h1.deep_merge(h2) { |key, old, new| Array.wrap(old) + Array.wrap(new) }
# #=> {:x => {:y => [4, 5, 6, 7, 8, 9]}, :z => [7, 8, 9, "xyz"]}
def deep_merge(other_hash, &block)
dup.deep_merge!(other_hash, &block)
end
# Same as +deep_merge+, but modifies +self+.
def deep_merge!(other_hash, &block)
other_hash.each_pair do |k,v|
tv = self[k]
if tv.is_a?(Hash) && v.is_a?(Hash)
self[k] = tv.deep_merge(v, &block)
else
self[k] = block && tv ? block.call(k, tv, v) : v
end
end
self
end
end
