Depth-first traversal on a hash

dft_example.rb

h = {
  foo: {
    bar: {
      baz: 1
    },
    oof: {
      zab: 2
    }
  },
  zha: {
    liz: {
      wng: 3,
      qan: 4
    }
  }
}

def dft(hash)
  path = []
  return path unless hash.is_a? Hash
  hash.each do |k, v|
    path << k
    path += dft(v)
  end
  path
end

p dft(h)
# [:foo, :bar, :baz, :oof, :zab, :zha, :liz, :wng, :qan]