Benchmarking var vs. attr vs. def

benchmark.rb

require "benchmark/ips"

class VarComponent
  def initialize(klass = nil)
    @class = klass

    @size = "w-48 h-64"
    @shadow = "shadow-md"
    @hover = "hover:bg-base-300 hover:scale-105 transition-transform"
    @structure = "flex flex-col items-start rounded-lg"
    @spacing = "gap-y-4 p-4"
    @color = "bg-base-200"
  end

  def view_template
    [@structure, @color, @hover, @size, @shadow, @spacing, @class]
  end
end

class AttrComponent
  attr_reader :size, :shadow, :hover, :structure, :spacing, :color

  def initialize(klass = nil)
    @class = klass

    @size = "w-48 h-64"
    @shadow = "shadow-md"
    @hover = "hover:bg-base-300 hover:scale-105 transition-transform"
    @structure = "flex flex-col items-start rounded-lg"
    @spacing = "gap-y-4 p-4"
    @color = "bg-base-200"
  end

  def view_template
    [structure, color, hover, size, shadow, spacing, @class]
  end
end

class DefComponent
  def initialize(klass = nil)
    @class = klass
  end

  def size = "w-48 h-64"
  def shadow = "shadow-md"
  def hover = "hover:bg-base-300 hover:scale-105 transition-transform"
  def structure = "flex flex-col items-start rounded-lg"
  def spacing = "gap-y-4 p-4"
  def color = "bg-base-200"

  def view_template
    [structure, color, hover, size, shadow, spacing, @class]
  end
end

Benchmark.ips do |x|
  x.report("VarComponent") { VarComponent.new.view_template }
  x.report("AttrComponent") { AttrComponent.new.view_template }
  x.report("DefComponent") { DefComponent.new.view_template }

  x.compare!
end

gistfile1.txt

$ ruby --yjit attr_vs_def.rb
ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +YJIT +PRISM [arm64-darwin24]
Warming up --------------------------------------
        VarComponent   327.614k i/100ms
       AttrComponent   327.468k i/100ms
        DefComponent   336.047k i/100ms
Calculating -------------------------------------
        VarComponent      3.525M (± 0.8%) i/s  (283.73 ns/i) -     17.691M in   5.019741s
       AttrComponent      3.488M (± 0.5%) i/s  (286.69 ns/i) -     17.683M in   5.069648s
        DefComponent      3.550M (± 2.4%) i/s  (281.66 ns/i) -     17.810M in   5.019447s

Comparison:
        DefComponent:  3550409.6 i/s
        VarComponent:  3524537.6 i/s - same-ish: difference falls within error
       AttrComponent:  3488137.8 i/s - same-ish: difference falls within error