deep_merge

Returns a new instance with the values from other merged recursively.

class Hash
  include ActiveSupport::DeepMergeable
end

hash_1 = { a: true, b: { c: [1, 2, 3] } }
hash_2 = { a: false, b: { x: [3, 4, 5] } }

hash_1.deep_merge(hash_2)
# => { a: false, b: { c: [1, 2, 3], x: [3, 4, 5] } }

A block can be provided to merge non-DeepMergeable values:

hash_1 = { a: 100, b: 200, c: { c1: 100 } }
hash_2 = { b: 250, c: { c1: 200 } }

hash_1.deep_merge(hash_2) do |key, this_val, other_val|
  this_val + other_val
end
# => { a: 100, b: 450, c: { c1: 300 } }