More readable integer comparisons in Ruby

Let’s be honest: comparison operators like <, >, <= and >= work perfectly fine, but they’re not so readable (even more so when you’re scanning through code quickly or working with complex conditionals).

What if instead of writing seats < 10 you could write seats.below? 10? Or usage.at_least? limit instead of usage >= limit? Much clearer, right?

This is where refinements come in handy (in short: add methods to existing classes without the risks of monkey patching).

Here’s a simple refinement module that I copy between my apps to make integer comparisons more expressive:

# lib/comparable_integer.rb (reusable modules and classes are stored in `lib/`)
module ComparableInteger
  refine Integer do
    def below?(other)
      self < other
    end

    def above?(other)
      self > other
    end

    def at_most?(other)
      self <= other
    end

    def at_least?(other)
      self >= other
    end
  end
end

Now imagine you’re building subscription logic that checks seat limits:

class SubscriptionsController < ApplicationController
  using ComparableInteger

  def upgrade
    if current_seats.below? requested_seats
      charge_additional_seats
      update_subscription

      redirect_to subscription_path, notice: "Upgraded successfully"
    else
      redirect_to subscription_path, alert: "Cannot downgrade seats"
    end
  end

  private

  def current_seats = @subscription.seats

  def requested_seats = params[:seats].to_i
end

The code reads almost like plain English. current_seats.below? requested_seats is immediately clear, while current_seats < requested_seats requires a mental translation.

Or another example when dealing with pricing tiers or feature limits:

class FeatureAccess
  using ComparableInteger

  def initialize(subscription)
    @subscription = subscription
  end

  def can_access_advanced_analytics?
    @subscription.amount_in_cents.at_least? 4999
  end

  def needs_team_plan?
    @subscription.seats.above? 1
  end

  def qualifies_for_discount?
    @subscription.months_active.at_least? 12
  end
end

Much more readable than a sea of >= and > symbols, don’t you think? Got more ideas for making Ruby code more expressive? Let me know in the comments below.

Over to you…

What did you like about this article? Learned something knew? Found something is missing or even broken? 🫣 Let me (and others) know!

Comments are powered by Chirp Form

More readable integer comparisons in Ruby

Want to read me more?