使用 Rails ERB 的条件 HTML 属性

Question

I've seen a few similar questions but none that appear generalisable to my situation.

I have to use HTML mixed with Ruby for some tags. There are two methods I have found.

Method A

<input id="<%= id %>" />

This works fine for the most part, however, if the id is an empty string or nil, then it will still return HTML like so:

<input id />

Problem: I'd prefer to exclude the 'id' tag completely if the variable is an empty string or nil.

Method B

<input <%= "id=#{id}" unless id.blank? %> />

If the id is an empty string it will return the desired result

<input />

Problem: If the id has multiple spaces, however, it causes issue (this is more relevant for tags like 'value'). For example if 'id' is "lorem ispum dolor sit amet" it would output:

<input id="lorem" ipsum dolor sit amet />

Does anyone have a better way of conditionally including HTML attributes? Note, I know I can use Rails HTML helpers like text_field_tag, but I'd like to find a solution without using those.

EDIT: I plan to do this with multiple HTML attributes (eg <input id="<%= id %>" value="<%= value %>" name="<%= name %>"... />

Answer 1

You can use the full structure of the condition:

<% unless id.blank? %>
  <input id="<%= id %>" />
<% else %>
  <input />
<% end %>