Feature/options for tags (#12)

* Add only_tags option
* Add including_tags option
* Add excluding_tags option
* Update docs

README.md

@@ -58,11 +58,24 @@ puts bidifier.apply('<div>input stringified html</div>')
 
 Available options with their default values are as follows:
 
+- `excluding_tags: []`
+
+    Removes tags from the list of bidifiable tags. This option affects the
+    provided tags in `including_tags` options.
+
+- `including_tags: []`
+
+    Adds new tags to the list of bidifiable tags
+
 - `greedy: false`
 
     By default, bidification stops when it reaches an element that has `dir`
     attribute. Use `true` to disregard any existing `dir` attributes.
 
+- `only_tags: []`
+
+    It sets the bidifiable tags to the given tags.
+
 - `with_table_support: false`
 
     Use `true` to add table tags support.

lib/bidify/bidifier.rb

@@ -23,6 +23,9 @@ def apply
     def configure
       @bidifiable_tags = DEFAULT_BIDIFIABLE_TAGS.dup
       @bidifiable_tags.concat(TABLE_TAGS) if @options[:with_table_support]
+      @bidifiable_tags.concat(@options[:including_tags]) if @options.key?(:including_tags)
+      @bidifiable_tags.delete_if { |tag| @options[:excluding_tags]&.include?(tag) }
+      @bidifiable_tags = @options[:only_tags] if @options.key?(:only_tags)
     end
 
     def bidify_recursively(html_node, options = {})

spec/html_string_bidifier_spec.rb

@@ -258,4 +258,72 @@
 
     expect(actual_output).to eq expected_output
   end
+
+  it 'only bidifies specified tags using `only_tags` option' do
+    input = <<~HTML
+      <p>راست left</p>
+      <div>left راست</div>
+    HTML
+
+    expected_output = <<~HTML
+      <p dir="auto">راست left</p>
+      <div>left راست</div>
+    HTML
+
+    bidifier = Bidify::HtmlStringBidifier.new(only_tags: ['p'])
+    actual_output = bidifier.apply(input)
+
+    expect(actual_output).to eq expected_output
+  end
+
+  it 'bidies specified additional tags using `including_tags` option' do
+    input = <<~HTML
+      <p>راست left</p>
+      <xyz>left راست</xyz>
+    HTML
+
+    expected_output = <<~HTML
+      <p dir="auto">راست left</p>
+      <xyz dir="auto">left راست</xyz>
+    HTML
+
+    bidifier = Bidify::HtmlStringBidifier.new(including_tags: ['xyz'])
+    actual_output = bidifier.apply(input)
+
+    expect(actual_output).to eq expected_output
+  end
+
+  it "doesn't bidify specified excluded tags using `excluding_tags` option" do
+    input = <<~HTML
+      <p>راست left</p>
+      <div>left راست</div>
+    HTML
+
+    expected_output = <<~HTML
+      <p dir="auto">راست left</p>
+      <div>left راست</div>
+    HTML
+
+    bidifier = Bidify::HtmlStringBidifier.new(excluding_tags: ['div'])
+    actual_output = bidifier.apply(input)
+
+    expect(actual_output).to eq expected_output
+  end
+
+  it '`excluding_tags` option overrides `including_tags`' do
+    input = <<~HTML
+      <p>راست left</p>
+      <xyz>left راست</xyz>
+    HTML
+
+    expected_output = <<~HTML
+      <p dir="auto">راست left</p>
+      <xyz>left راست</xyz>
+    HTML
+
+    bidifier = Bidify::HtmlStringBidifier.new(including_tags: ['xyz'], excluding_tags: ['xyz'])
+    actual_output = bidifier.apply(input)
+
+    expect(actual_output).to eq expected_output
+  end
 end