Deprecate `button_to_function` and `link_to_function` helpers.

We recommend the use of Unobtrusive JavaScript instead. For example:

  link_to "Greeting", "#", :class => "nav_link"

  $(function() {
    $('.nav_link').click(function() {
      // Some complex code

      return false;
    });
  });

or

  link_to "Greeting", '#', onclick: "alert('Hello world!'); return false", class: "nav_link"

for simple cases.

This reverts commit 3acdd652e9fe99481c879c84c5807a84eb9ad724.

3 files changed, 104 insertions, 2 deletions

diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 236768227c..7a9c2a3fa9 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,5 +1,27 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Deprecate `button_to_function` and `link_to_function` helpers.
+
+    We recommend the use of Unobtrusive JavaScript instead. For example:
+
+      link_to "Greeting", "#", :class => "nav_link"
+
+      $(function() {
+        $('.nav_link').click(function() {
+          // Some complex code
+
+          return false;
+        });
+      });
+
+    or
+
+      link_to "Greeting", '#', onclick: "alert('Hello world!'); return false", class: "nav_link"
+
+    for simple cases.
+
+    *Rafael Mendonça França*
+
 *   `javascript_include_tag :all` will now not include `application.js` if the file does not exists. *Prem Sichanugrist*
 
 *   Send an empty response body when call `head` with status between 100 and 199, 204, 205 or 304.
@@ -146,8 +168,6 @@
 *   Replace `include_seconds` boolean argument with `:include_seconds => true` option
     in `distance_of_time_in_words` and `time_ago_in_words` signature. *Dmitriy Kiriyenko*
 
-*   Remove `button_to_function` and `link_to_function` helpers. *Rafael Mendonça França*
-
 *   Make current object and counter (when it applies) variables accessible when
     rendering templates with :object / :collection. *Carlos Antonio da Silva*
 
diff --git a/actionpack/lib/action_view/helpers/javascript_helper.rb b/actionpack/lib/action_view/helpers/javascript_helper.rb
index cc20518b93..9f8cd8caaa 100644
--- a/actionpack/lib/action_view/helpers/javascript_helper.rb
+++ b/actionpack/lib/action_view/helpers/javascript_helper.rb
@@ -67,6 +67,46 @@ module ActionView
       def javascript_cdata_section(content) #:nodoc:
         "\n//#{cdata_section("\n#{content}\n//")}\n".html_safe
       end
+
+      # Returns a button whose +onclick+ handler triggers the passed JavaScript.
+      #
+      # The helper receives a name, JavaScript code, and an optional hash of HTML options. The
+      # name is used as button label and the JavaScript code goes into its +onclick+ attribute.
+      # If +html_options+ has an <tt>:onclick</tt>, that one is put before +function+.
+      #
+      #   button_to_function "Greeting", "alert('Hello world!')", :class => "ok"
+      #   # => <input class="ok" onclick="alert('Hello world!');" type="button" value="Greeting" />
+      #
+      def button_to_function(name, function=nil, html_options={})
+        message = "button_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead."
+        ActiveSupport::Deprecation.warn message
+
+        onclick = "#{"#{html_options[:onclick]}; " if html_options[:onclick]}#{function};"
+
+        tag(:input, html_options.merge(:type => 'button', :value => name, :onclick => onclick))
+      end
+
+      # Returns a link whose +onclick+ handler triggers the passed JavaScript.
+      #
+      # The helper receives a name, JavaScript code, and an optional hash of HTML options. The
+      # name is used as the link text and the JavaScript code goes into the +onclick+ attribute.
+      # If +html_options+ has an <tt>:onclick</tt>, that one is put before +function+. Once all
+      # the JavaScript is set, the helper appends "; return false;".
+      #
+      # The +href+ attribute of the tag is set to "#" unless +html_options+ has one.
+      #
+      #   link_to_function "Greeting", "alert('Hello world!')", :class => "nav_link"
+      #   # => <a class="nav_link" href="#" onclick="alert('Hello world!'); return false;">Greeting</a>
+      #
+      def link_to_function(name, function, html_options={})
+        message = "link_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead."
+        ActiveSupport::Deprecation.warn message
+
+        onclick = "#{"#{html_options[:onclick]}; " if html_options[:onclick]}#{function}; return false;"
+        href = html_options[:href] || '#'
+
+        content_tag(:a, name, html_options.merge(:href => href, :onclick => onclick))
+      end
     end
   end
 end
diff --git a/actionpack/test/template/javascript_helper_test.rb b/actionpack/test/template/javascript_helper_test.rb
index fe7607ee26..4a9a382afa 100644
--- a/actionpack/test/template/javascript_helper_test.rb
+++ b/actionpack/test/template/javascript_helper_test.rb
@@ -42,6 +42,48 @@ class JavaScriptHelperTest < ActionView::TestCase
     assert_instance_of ActiveSupport::SafeBuffer, escape_javascript(ActiveSupport::SafeBuffer.new(given))
   end
 
+  def test_button_to_function
+    assert_deprecated "button_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead." do
+      assert_dom_equal %(<input type="button" onclick="alert(&#x27;Hello world!&#x27;);" value="Greeting" />),
+        button_to_function("Greeting", "alert('Hello world!')")
+    end
+  end
+
+  def test_button_to_function_with_onclick
+    assert_deprecated "button_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead." do
+      assert_dom_equal "<input onclick=\"alert(&#x27;Goodbye World :(&#x27;); alert(&#x27;Hello world!&#x27;);\" type=\"button\" value=\"Greeting\" />",
+        button_to_function("Greeting", "alert('Hello world!')", :onclick => "alert('Goodbye World :(')")
+    end
+  end
+
+  def test_button_to_function_without_function
+    assert_deprecated "button_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead." do
+      assert_dom_equal "<input onclick=\";\" type=\"button\" value=\"Greeting\" />",
+        button_to_function("Greeting")
+    end
+  end
+
+  def test_link_to_function
+    assert_deprecated "link_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead." do
+      assert_dom_equal %(<a href="#" onclick="alert(&#x27;Hello world!&#x27;); return false;">Greeting</a>),
+        link_to_function("Greeting", "alert('Hello world!')")
+    end
+  end
+
+  def test_link_to_function_with_existing_onclick
+    assert_deprecated "link_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead." do
+      assert_dom_equal %(<a href="#" onclick="confirm(&#x27;Sanity!&#x27;); alert(&#x27;Hello world!&#x27;); return false;">Greeting</a>),
+        link_to_function("Greeting", "alert('Hello world!')", :onclick => "confirm('Sanity!')")
+    end
+  end
+
+  def test_function_with_href
+    assert_deprecated "link_to_function is deprecated and will be removed from Rails 4.1. Use Unobtrusive JavaScript instead." do
+      assert_dom_equal %(<a href="http://example.com/" onclick="alert(&#x27;Hello world!&#x27;); return false;">Greeting</a>),
+        link_to_function("Greeting", "alert('Hello world!')", :href => 'http://example.com/')
+    end
+  end
+
   def test_javascript_tag
     self.output_buffer = 'foo'