Insert element at the beginning of Ruby Hash?

Question

I have a use-case where I have an existing hash:

response = { aa: 'aaa', bb: 'bbb' }

I need to add id as one of the keys.

When I use response.merge(id: 'some_id') and then convert it into JSON, I got id as the last element, which I don't want.

I want to insert id: 'some_id' at the beginning of response. I have tried this, but it doesn't feel good to iterate over it:

new_response = { id: 'some id' }
response.keys.reverse.each {|key| new_response[key] = response[key] }

Basically, I need a similar feature like Ruby Array's unshift.

irb(main):042:0> arr = [1, 2, 3]
=> [1, 2, 3]
irb(main):043:0> arr.unshift(5)
=> [5, 1, 2, 3]

Answer 1

response = {aa: 'aaa', bb: 'bbb'}
new_response = {new: 'new_value'}.merge(response)
# => {:new=>"new_value", :aa=>"aaa", :bb=>"bbb"}

Answer 2

Try converting it to an array and back:

Hash[hash.to_a.unshift([k, v])]