Hash extensions

Hash.rb

class Hash
  def sample(n = 1)
    Hash[to_a.sample(n)]
  end
  
  def deep_flatten
    flat_map { |k, v| [k, *(v.respond_to?(:deep_flatten) ? v.deep_flatten : v)] }
  end

  def flat_join_keys(prefix: nil, separator: '-', memo: {})
    each do |key, value|
      joined_key = [prefix, key].compact.join(separator).underscore.to_sym

      if value.respond_to?(:flat_join_keys)
        value.flat_join_keys(prefix: key, memo: memo)
      else
        memo[joined_key] = value
      end
    end

    memo
  end
end

• Hash#sample(n = 1): retrieve n number of random key/value pairs out of hash

• Hash#deep_flatten: flatten hash into one dimensional Array, ie:

{
  level1_a: {
    level2_a: :hello,
    level2_b: :world,
  },
  level1_b: :hi,
}

becomes

[:level1_a, :level2_a, :hello, :level2_b, :world, :level1_b, :hi]

• Hash#flat_join_keys: flatten a multi-dimensional hash down to one level, joining parent keys with sub-keys, ie:

{
    level1_a: {
    level2_a: 'hello',
    level2_b: 'world',
  },
  level1_b: 'hi!'
}

becomes

{
  level1_a_level2_a: 'hello',
  level1_a_level2_b: 'world',
  level1_b: 'hi!',
}