Compares the time difference when running webpack between 2 sets of changes/branches

webpack_benchmark.rb

# frozen_string_literal: true

# Instructions
# 1- Copy this file to /tmp
# 2- Switch to the baseline branch
# 3- Run "ruby webpack_benchmark.rb"
# 4- Switch branches and run this script again

require 'benchmark'

aggregate_run_time = 0

number_of_runs = 10
number_of_runs.times do
  # Benchmark the build script
  results = Benchmark.measure do
    `
      cd ..
      npx webpack --config webpack.production.js
    `
  end

  # Get the results
  aggregate_run_time += results.real.round(3)
end

# Calculate averages
current_average_time = (aggregate_run_time / number_of_runs).round(3)
puts "Average time after #{number_of_runs} runs: #{current_average_time}"

# Read baseline
if File.file?("webpack_benchmark_baseline.txt")
  baseline_time = File.read("webpack_benchmark_baseline.txt").to_f
  time_difference = (100 - ((current_average_time * 100) / baseline_time)).round(2)
  puts "This run is #{time_difference}% #{ current_average_time > baseline_time ? "slower" : "faster" } than the baseline (#{baseline_time})"

# Create a baseline
else
  File.open("webpack_benchmark_baseline.txt", 'w') { |file| file.write(current_average_time) }
end