acts_as_taggable_on meets thinking_sphinx on rails (and nearly misses it)

Beware, for reasons unknown, instead of
indexes tags.name, :as => :tags
you have to write
indexes taggings.tag.name, :as => :tags
or you'll get too many results.

jQuery autoSuggest vs rails (and acts_as_taggable_on)

While AutoSuggest is quite wonderful as it is, there's also a lot of room for improvement (e.g. I've started using this fork since the original author doesn't seem too community-friendly).

Here's one tip on how to use it with rails (and simple_form) — or rather how to workaround the following issue.
When you write something like $("#post_tag_list").autoSuggest(...); for the first time, you'll expect AS to do all the wow stuff on the client side and have the original input field with the values as a parameter back on the server side, right?
Well, I did.
Unfortunately, you have to work harder: not only you must include the asHtmlID: "tag_list" option in the autoSuggest parameters, but (since that option actually defines the id's suffix only) you'll have to patch your controller allong the lines of:
before_filter :autosuggest_fix
def autosuggest_fix
params[:post][:tag_list] = params[:as_values_tag_list] if params[:post]

a jQuery templates tip: checking for optional fields

One tip regarding the templates

“Comments for this page are closed.” for some reason, so here:
When rendering an optional numerical field, the safest way to check on its existence is:
{{if typeof $item.data.optional_field == "number"}}...{{/if}}
(for other types, change the right side of the == accordingly)

The main problem with the way described in the doc is possible accidental name collision of the field's name with some other variable in the scope.



Array(x) is syntax cool, it will return an empty array for nil, a one-item array for an item, and a copy of the array for an array.