Question

Which is better?

1.

= link_to "Page", "/page", :class => "button", :data => {:theme => "green", :icon => "small-arrow"}

2.

= link_to "Page", "/page", class: "button", data: {theme: "green", icon: "small-arrow"}

3.

= link_to "Page", "/page", class: :button, data: {theme: :green, icon: "small-arrow"}

I found out that the symbols are the best way to use because of the memory alocation difference between symbols and strings.

I find version 2. as more readable (for me) and i think also more maintainable, because it’s easier/faster to see/edit/add separated words (by space or dash) inside a string rather than edit a symbol and transform it to a string (when needed, like adding a second class “button login” or other theme “dark-red”, for example).

Is there any serious reason (e.g. performance) to use the notation from 1. or 3. rather than 2.?

Answer 1

Note that it’s not only about symbols, it’s about old and new hash syntax.

I don’t like to mix new hash syntax with symbols. New syntax looks well in most cases, for example:

{ width: 42, height: 24 }

But it looks horrible with symbols:

... class: :button ...

It is weird and not human readable, in my opinion. I dislike 3rd option. So, I prefer this option (you didn’t mention it):

= link_to "Page", "/page", :class => :button, 
   :data => { :theme => :green, :icon => "small-arrow" }

This is better because :class symbol is written similar to :button symbol. Symbols should be written in the same syntax in a single line.