How to avoid NoMethodError for missing elements in nested hashes, without repeated nil checks?

hash, hash-of-hashes, ruby, ruby-on-rails

Solution

Ruby 2.3.0 introduced a method called `dig` on both `Hash` and `Array`.

name = params.dig(:company, :owner, :name)

It returns `nil` if the key is missing at any level.

If you are using a version of Ruby older than 2.3, you can install a gem such as `ruby_dig` or `hash_dig_and_collect`, or implement the functionality yourself:

module RubyDig
  def dig(key, *rest)
    if value = (self[key] rescue nil)
      if rest.empty?
        value
      elsif value.respond_to?(:dig)
        value.dig(*rest)
      end
    end
  end
end

if RUBY_VERSION < '2.3'
  Array.send(:include, RubyDig)
  Hash.send(:include, RubyDig)
end

Problem

I'm looking for a good way to avoid checking for `nil` at each level in deeply nested hashes. For example: ``` name = params[:company][:owner][:name] if params[:company] && params[:company][:owner] && params[:company][:owner][:name] ``` This requires three checks, and makes for very ugly code. Any way to get around this?

Original source

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