Rails does a great job at many things, but one of the most consistent stumbling blocks I see in #rubyonrails is RJS. It complicates many things that just don’t need to be that complex, especially when using a Javascript helper library like Prototype or jQuery.

Keep things simple! One little helper, and your AJAX requests get a whole lot easier to manage. This was inspired by the now-defunct MinusMOR.

def js(data)
  data.respond_to?(:to_json) && data.to_json || data.inspect.to_json
end

Now, when you want to render a Javascript view, you can use just straight Javascript. For example, if you would like to update a given element in your page with the contents of a partial, save a template, something like update.js.erb, with the following:

$("div#post_<%=@post.id%>").update(<%=js render(:partial => "post.html.erb", :object => @post) %>);

This is admittedly more complex than RJS in the simple case, but what about when you want to do more complex stuff, like this vote.js.erb template?

<% unless @msg.nil? %>
statusMessage(<%=js @msg%>);
<% end %>
var obj = $$('div#post_<%=@post.id%> span.vote a');
for(var i=0; i<obj.length; i++) {
	var e = obj[i];
	e.update(<%=js "+#{@post.vote_score}"%>);
	e.addClassName("voted_post");
}

Just as easy as writing any of your other views, and won’t get in your way when you need to go some fancy Javascript gymnastics without requiring ugly heredocs cluttering up the code all over.

How about passing an Array to a client-side Javascript function?

runSomeUpdateFunctionThatTakesAJavascriptArray(<%=js @list_of_values %>)

No worries about malformed Javascript!