Is there a way to use a Ruby loop inside of HAML's :javascript region?

Question

Inside of HAML, can we have a loop inside the :javascript region?

This will work:

- 10.upto(20) do |i|
  :javascript
    document.getElementById(\'aD         


        

Answer 1

%html
  %head
    :javascript
      var foo = [];
      #{
        limit = rand(4)+3
        array = (0..limit).to_a
        array.map{ |i| "foo[#{i}] = #{rand(12)};" }.join ' '
      }
      console.log(foo.length);
    %body

Running the above code gives this output:

As you can see, the big #{...} block (which may span multiple lines) runs arbitrary Ruby code. The result of the last expression (in this case the map{...}.join) is converted to a string and placed in the output.

Edit for Radek: If you want to declare a variable inside you Haml template, inside your JavaScript filter (which seems like an odd desire), then you need to be sure that the result of the block to_s doesn't produce unwanted output:

This Haml...

%p
  :javascript
    var foo = 12;
    #{x = 42}
    var bar = #{x};

...produces this HTML:

Whereas this Haml...

%p
  :javascript
    var foo = 12;
    #{x = 42; ""}
    var bar = #{x};

...produces this HTML...

But before you do this, ask yourself: why am I creating complex Ruby variables in my view?
Shouldn't this variable have been declared by my controller?