ruby

Ruby

Expert Ruby development with modern idioms, performance patterns, and testing best practices.

Language & Style

• Use frozen_string_literal: true at the top of every file to reduce object allocations
• Prefer symbol.to_proc for simple enumerables: users.map(&:name) over users.map { |u| u.name }
• Use keyword arguments for methods with 2+ optional params; avoids positional confusion
• Avoid rescue Exception — rescue StandardError or specific subclasses only
• Use Struct.new(:a, :b, keyword_init: true) for lightweight value objects
• Prefer then / yield_self for pipeline-style transformations over deep nesting

Memory & Performance

• Use lazy enumerators for large collections: (1..Float::INFINITY).lazy.select { ... }.first(10)
• Avoid creating unnecessary strings in loops; use symbols where semantics allow
• Use frozen_string_literal and String#dup only when mutation is needed
• Profile with ruby-prof or stackprof before optimizing; don't guess

Testing with RSpec

# Describe behavior, not implementation
RSpec.describe Order do
  describe '#total' do
    subject(:order) { described_class.new(items: [item]) }
    let(:item) { build(:item, price: 9.99) }

    it 'sums item prices' do
      expect(order.total).to eq(9.99)
    end
  end
end

• Use let for lazy setup, let! only when the side effect is required before the example
• Prefer described_class over hardcoding the class name
• Use FactoryBot factories for complex models; avoid fixtures
• Use aggregate_failures to report all failures in one example rather than stopping at first

Sidekiq (Background Jobs)

class EmailWorker
  include Sidekiq::Job
  sidekiq_options retry: 3, queue: :mailers

  def perform(user_id)
    user = User.find(user_id)
    UserMailer.welcome(user).deliver_now
  end
end

# Enqueue
EmailWorker.perform_async(user.id)
EmailWorker.perform_in(5.minutes, user.id)

• Always pass serializable primitives (IDs, strings) — never pass ActiveRecord objects
• Set explicit retry counts per job; rely on exponential backoff for transient failures
• Use Sidekiq::Testing.fake! in tests; assertions via EmailWorker.jobs.size