Get leaf_keys from any hash

[Tobias-Knudsen]

Example Usage:

nested_hash = {
  a: {
    x: 1,
    y: { z: 2 }
  },
  b: {
    m: { n: 3, o: 4 },
    p: 5
  },
  c: 6
}

result = leaf_keys(nested_hash)
puts result => [:x, :z, :n, :o, :p, :c]

We might want to get the set of unique leaf keys back by default

Suggested solution

def leaf_keys
  each_with_object([]) do |(key, value), result|
    if value.is_a?(Hash) && !value.empty?
      result.concat(value.leaf_keys)
    else
      result << key
    end
  end.uniq
end