ERB::Linter

It's all too easy to introduce errors inside ERB files, unclosed tags, wrong attribute names, bad indentation.

ERB::Linter can check for those errors by turning your ERB tags into HTML-ish tags and run a proper HTML linter on the result:

original ERB

<div>
  <% if @foo == :bar %>
    <%= image_tag(item[:value], alt: item[:value]) %>
  <% elsif @type == :other %>
    <span><%= item[:value] %></span>
  <% else %>
    <% raise "unknown type" %>
  <% end %>
</div>

generated HTML, for linter consumption

<div>
  <erb silent erb-code=" if @foo == :bar ">
    <erb loud erb-code=" image_tag(item[:value], alt: item[:value]) "></erb>
  </erb>
  <erb silent erb-code=" elsif @type == :other ">
    <span><erb loud erb-code=" item[:value] "></erb></span>
  </erb>
  <erb silent erb-code=" else ">
    <erb silent erb-code=" raise &quot;unknown type&quot; "></erb>
  </erb>
</div>

Installation

Add this line to your application's Gemfile:

gem 'erb-linter'

And add linthtml to yarn:

$ yarn add --dev @linthtml/linthtml

Usage

From the command line

ruby -rbundler/setup -rerb/linter -e "exit ERB::Linter::Checker.check_files('app/views/**/*.html.erb')"

As a Rake task

Add a task to your Rakefile:

ERB::Linter::Task.new do |task|
  # Change the task name.
  # Default: :erb_linter
  # task.name = 'linter:html'

  # Use a different glob for listing ERB files.
  # Default: '**/*.erb'
  # task.glob = 'app/components/**/*.html.erb'

  # Use a different temp dir for storing the HTML version of your ERB files.
  # Default: Dir.tmpdir
  # task.tmpdir = Rails.root.join('tmp')
end

Example linthtml configuration

And then add a linthtml configuration like this:

.linthtmlrc.js

module.exports = {
  maxerr: false,
  "raw-ignore-regex": false,
  "attr-bans": [
    "align",
    "background",
    "bgcolor",
    "border",
    "frameborder",
    "longdesc",
    "marginwidth",
    "marginheight",
    "scrolling",
    "style",
    "width",
  ],
  "indent-delta": false,
  "indent-style": "spaces",
  "indent-width": 2,
  "indent-width-cont": false,
  "spec-char-escape": true,
  "text-ignore-regex": false,
  "tag-bans": ["style", "b"],
  "tag-close": true,
  "tag-name-lowercase": true,
  "tag-name-match": true,
  "tag-self-close": false,
  "doctype-first": false,
  "doctype-html5": false,
  "attr-name-style": "dash",
  "attr-name-ignore-regex": false,
  "attr-no-dup": true,
  "attr-no-unsafe-char": true,
  "attr-order": false,
  "attr-quote-style": "double",
  "attr-req-value": false,
  "attr-new-line": false,
  "attr-validate": true,
  "id-no-dup": true,
  "id-class-no-ad": false,
  "id-class-style": false, // "lowercase", "underscore", "dash", "camel", "bem"
  "class-no-dup": true,
  "class-style": false,
  "id-class-ignore-regex": false,
  "img-req-alt": true,
  "img-req-src": true,
  "html-valid-content-model": true,
  "head-valid-content-model": true,
  "href-style": false,
  "link-req-noopener": true,
  "label-req-for": false,
  "line-end-style": "lf",
  "line-no-trailing-whitespace": true,
  "line-max-len": false,
  "line-max-len-ignore-regex": false,
  "head-req-title": true,
  "title-no-dup": true,
  "title-max-len": 60,
  "html-req-lang": false,
  "lang-style": "case",
  "fig-req-figcaption": false,
  "focusable-tabindex-style": false,
  "input-radio-req-name": true,
  "input-req-label": false,
  "table-req-caption": false,
  "table-req-header": false,
  "tag-req-attr": false,
};

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/nebulab/erb-linter.

License

The gem is available as open source under the terms of the MIT License.