HAML → ERB (context: https://twitter.com/javan/status/1483610684281835523)

haml.rake

namespace :haml do
  desc "Convert HAML templates to ERB"
  task :convert_to_erb do
    # Assumes you have faraday in your Gemfile
    conn = Faraday.new(url: "https://haml2erb.org") do |f|
      f.request :json
      f.response :json
    end

    haml_filenames = Dir["app/views/**/*.haml"]
    failures = []

    puts "Converting #{haml_filenames.size} .haml templates…"

    haml_filenames.each do |haml_filename|
      haml_file = Pathname.new(haml_filename)

      haml = ""
      haml_file.read.strip.each_line(chomp: true) do |line|
        # Replace {"foo": "bar"} with {"foo" => "bar"}
        line.gsub!(/": /, '" => ') if line.match? /{.*".+":.*}/
        
        # WARNING: These lines are potentially buggy / destructive. Uncomment to live dangerously.
        #
        # # Replace {data: {foo: "bar"}} with {"data-foo" => "bar"}
        # line.gsub!(/data:.*{(.+)}/) { $1.gsub(/(\w+):/) { "\"data-#{$1.dasherize}\" =>" } } if line.match? /{.*data: {.+}.*}/
        # # Replace {aria: {foo: "bar"}} with {"aria-foo" => "bar"}
        # line.gsub!(/aria:.*{(.+)}/) { $1.gsub(/(\w+):/) { "\"aria-#{$1.dasherize}\" =>" } } if line.match? /{.*aria: {.+}.*}/
        #

        haml << "#{line}\n" if line.present?
      end

      response = conn.post("/api/convert", { haml: haml })

      erb = response.body["erb"] if response.success? && response.body["success"]

      if erb.present? && !erb.match?(/\(line \d+, column \d+\)/) # haml2erb encountered an error, but returned "success" 🤷‍♂️
        erb = response.body["erb"]
        # Replace <%= # … %> with <%# … %>
        erb.gsub!("<%= #", "<%#")
        erb_filename = haml_filename.sub(/\.haml$/, ".erb")
        erb_file = Pathname.new(erb_filename)
        erb_file.write(erb)
        haml_file.unlink
        puts "✅ #{haml_filename} → #{erb_filename}"
      else
        failures << haml_filename
        error = response.body["error"].presence || erb.presence || ""
        puts "❌ #{haml_filename}: #{error.squish}"
      end

      sleep 0.3
    end

    puts "Done! Converted #{haml_filenames.size - failures.size} of #{haml_filenames.size} templates."
    if failures.any?
      puts "Failures:"
      failures.each { puts "  #{_1}" }
    end
  end
end

license

The MIT License (MIT)

Copyright (c) 2022 Javan Makhmali

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

Thanks for posting this! I'm converting a lot of HAML -> ERB and this is very helpful. There are a lot of data: {} and aria: {} hash attributes in the HAML I'm converting and I figured I'd share one insight regarding your commented out regex replacements.

In this case there is an interpolated ruby value within a string inside a nested data attribute, i.e.:

data: {select_upgrade_finish: "finish-#{color.id}"}

The current gsub-ing would output color.id}. If I adjust the regex to use [^"]* instead of .* it works in this case:

line.gsub!(/data:[^"]*{(.+)}/) { $1.gsub(/(\w+):/) { "\"data-#{$1.dasherize}\" =>" } } if line.match? /{.*data: {.+}.*}/