Ruby Weekly Challenge - Valid Braces

valid_braces.rb

def valid_braces(braces)
  BracesValidator.new(braces).valid_braces?
rescue
  return false
end

# most succinct
def validBraces(braces)
  while braces.gsub!(/\(\)|\{\}|\[\]/, '') do ; end
  braces.empty?
end

class BracesValidator
  attr_reader :braces_array

  def initialize(braces_string)
    fail ArgumentError unless valid_braces_string?(braces_string)
    @braces_array = braces_string.split("")
  end

  def valid_braces?
    balanced?(braces_array, [])
  end

  private

  def valid_braces_string?(braces_string)
    braces_string && !braces_string.empty? && braces_string.length % 2 == 0
  end

  def balanced?(braces_array, stack)
    return stack.empty? if braces_array.empty?

    b = braces_array.shift
    if(open?(b))
      return balanced?(braces_array, stack.push(b))
    elsif(closed?(b))
      return !stack.empty? && matching?(stack.pop, b) && balanced?(braces_array, stack)
    end
  end

  def matching?(o, c)
    lookup[o] == c
  end

  def open?(o)
    lookup.keys.include? o
  end

  def closed?(c)
    !open?(c)
  end

  def lookup
    @lookup ||= {
      "(" => ")",
      "{" => "}",
      "[" => "]"
    }
  end
end

valid_braces_spec.rb

require_relative '../valid_braces'

describe "#valid_braces" do
  context "when valid" do
    it "returns true" do
      expect(valid_braces("(){}[]")).to be_truthy
    end

    it "return true" do
      expect(valid_braces("([{}])")).to be_truthy
    end

    it "return true" do
      expect(valid_braces("()")).to be_truthy
    end
    
    it "returns true" do 
      expect(valid_braces("(({{[[]]}}))")).to be_truthy
    end

    it "returns true" do
      expect(valid_braces("({})[({})]")).to be_truthy
    end
  end

  context "when invalid" do
    it "returns false" do
      expect(valid_braces(nil)).to be_falsey
    end

    it "returns false" do
      expect(valid_braces("")).to be_falsey
    end

    it "returns false" do
      expect(valid_braces("(")).to be_falsey
    end

    it "returns false" do
      expect(valid_braces("(}")).to be_falsey
    end

    it "returns false" do
      expect(valid_braces("[(])")).to be_falsey
    end

    it "returns false" do
      expect(valid_braces("][")).to be_falsey
    end

    it "returns false" do
      expect(valid_braces("({[)}]")).to be_falsey
    end
  end
end