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Ruby methods within Javascript within HAML

Posted by: admin November 30, 2017 Leave a comment

Questions:

I have a jQuery script that adds a new field to a form, and this field contains dynamic information from an array. The problem is that I can’t figure out how to add an array.each to populate the options of the select field within the javascript without breaking the HAML indentation and causing errors.

Here is my best attempt that does not work:

%script(type="text/javascript")  
  $('#mylink').click(function() {  
  $('#mylink').after('<select>  
  - myarray.each do |options|  
     <option value="#{options.id}">#{options.name}</option>  
  </select>);  
  )};

Also tried it with the :javascript filter with no luck.

Answers:

Usually, if something is a pain in haml, it means you should refactor the the tricky bit to a helper or partial and call that.

// some_helper.rb
def new_snazzy_select_tag(options = [])
  select_tag 'tag_name_here', options.map { |option| [option.id, option.name] }
end

Also, you should use the :javascript filter to render javascript since it will put it in a script tag for you and allow indentation.

Lastly, you can use #{ruby_expression} anywhere in haml, including :javascript filters, which is very handy when you need to output the result of ruby expressions to places that are not directly contents of html elements.

// some_view.html.haml
:javascript
  $('#mylink').click(function() {  
    $('#mylink').after("#{escape_javascript new_snazzy_select_tag(myarray)}");
  };

Questions:
Answers:

Try this, it should work (all i did was remove a single space in the fifth line and add the closing quote on the sixth):

%script(type="text/javascript")
  $('#mylink').click(function() {
  $('#mylink').after('<select>
  - @myarray.each do |options|
    <option value="#{options.id}">#{options.name}</option>
  </select>');
  )};

However, assuming you’re running this with a ruby script or framework of sorts, why not just do it outside the template? That would probably be most appropriate. In rails/sinatra and other frameworks, you could use a helper method to do this. If you look at the haml reference, they actually discourage use of - to evaluate ruby.