Class: Rails::CssUnused::ViewScanner

Inherits:
Object
  • Object
show all
Defined in:
lib/rails/css_unused/view_scanner.rb

Overview

Scans Rails view templates, ViewComponent files, Phlex components, Stimulus controllers, and Ruby files for referenced CSS class names.

Handles:

ERB:       class="foo bar",  class: "foo",  class: ["foo", "bar"]
HAML:      .foo.bar,  %div.foo
Slim:      div.foo,  .foo
Ruby:      html_class: "foo",  css_classes("foo bar"),  "foo bar"
Stimulus:  this.element.classList.add("foo"),  "foo" string literals
Dynamic:   class="<%= cond ? 'foo' : 'bar' %>" — literal parts extracted
Dynamic vars: status_class = "foo-bar" — string assigned to *_class/*_classes var

Constant Summary collapse

HTML_CLASS_ATTR =

── ERB / HTML patterns ──────────────────────────────────────────────class=“foo bar baz” or class=‘foo bar’

/class\s*=\s*["']([^"'<>]+)["']/i
RUBY_CLASS_KV =

class: “foo bar” or class: ‘foo’

/class:\s*["']([^"']+)["']/
RUBY_CLASS_ARRAY =

class: [“foo”, “bar”] or class: %w[foo bar]

/class:\s*(?:\[|%w\[)\s*([^\]\n]+)/
TAG_HELPER =

tag.div(class: “foo”) content_tag(:div, class: “foo”)

/(?:content_tag|tag\.\w+)\s*[({][^)}\n]*class:\s*["']([^"']+)["']/
HAML_IMPLICIT =

── HAML patterns ───────────────────────────────────────────────────.foo, %div.foo.bar, %span.foo#id

/^[ \t]*(?:%[\w:-]+)?(\.[a-zA-Z][a-zA-Z0-9_-]*(?:\.[a-zA-Z][a-zA-Z0-9_-]*)*)/
HAML_HASH_CLASS =

Inline { class: “foo” }

/class:\s*["']([^"']+)["']/
SLIM_CLASS =

── Slim patterns ───────────────────────────────────────────────────div.foo.bar or .foo.bar on its own line

/^[ \t]*(?:[\w-]*)(\.[a-zA-Z][a-zA-Z0-9_-]*(?:\.[a-zA-Z][a-zA-Z0-9_-]*)*)/
ERB_DYNAMIC_CLASS =

── ERB dynamic interpolation ────────────────────────────────────────class=“<%= expr %>”, class=“prefix-<%= var %>” — extracts static parts

/class\s*=\s*["'][^"']*<%=[^%]+%>[^"']*["']/m
DYNAMIC_CLASS_VAR =

── Dynamic class variable detection (v0.2.1) ────────────────────────Detects string literals assigned to variables whose name ends with _class, _classes, _style, or _css — and the string contains hyphens (Ruby variable names cannot contain hyphens, so it must be a value).

Matches patterns like:

status_class = "foo-bar"
button_classes = "btn btn-primary"
["Active", "status-active"]          (array element with hyphenated string)
["Cancelled", "status-cancelled"]

Rule: any double- or single-quoted string containing at least one hyphen is unambiguously a string value (not a Ruby identifier), so we can safely extract it as a potential class name.

Pattern 1: variable ending in _class/_classes/_style/_css = “value”

/\b\w+_(?:class(?:es)?|style|css)\s*=\s*["']([^"'\n]+)["']/
HYPHENATED_STRING =

Pattern 2: any quoted string with hyphens in array/tuple context e.g. [“Active”, “status-active”] — the hyphenated strings are CSS classes

/["']([a-zA-Z][a-zA-Z0-9]*(?:-[a-zA-Z0-9]+)+)["']/
JS_ADD_CLASS =

── Ruby / Stimulus string literals ─────────────────────────────────Any double-quoted string that looks like a space-separated class list

/(?:classList\.add|classList\.toggle|classList\.replace)\s*\(\s*["']([^"']+)["']/
JS_REMOVE_CLASS = 
/(?:classList\.remove)\s*\(\s*["']([^"']+)["']/
RUBY_STRING_CLASSES = 
/["']([a-zA-Z][a-zA-Z0-9_-]*(?:\s+[a-zA-Z][a-zA-Z0-9_-]*)*)[\"']/

Instance Method Summary collapse

Constructor Details

#initialize(root:, config: CssUnused.configuration) ⇒ ViewScanner

Returns a new instance of ViewScanner.



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# File 'lib/rails/css_unused/view_scanner.rb', line 69

def initialize(root:, config: CssUnused.configuration)
  @root   = Pathname(root)
  @config = config
end

Instance Method Details

#used_classes ⇒ Object

Returns a Set of class name strings referenced across all view files.



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# File 'lib/rails/css_unused/view_scanner.rb', line 75

def used_classes
  classes     = Set.new
  ignore_set  = @config.ignore_classes.map(&:to_s).to_set
  ignore_pats = Array(@config.ignore_patterns)

  each_view_file do |path, content|
    extract_from(content, path).each do |cls|
      next if ignore_set.include?(cls)
      next if ignore_pats.any? { |p| cls.match?(p) }
      classes << cls
    end
  end

  if @config.scan_javascript_for_classes
    each_js_file do |path, content|
      extract_js_classes(content).each { |cls| classes << cls }
    end
  end

  classes
end