This is a nice trick that is useful, for example if you need to send an html string via an api endpoint.
Instead of constructing the string manually like this:
# api controller @title = "some title" @html_string ="<h1>[email protected]}</h1>"
You can put the template into a template file, for example ‘html_string.erb’, and call ‘render_to_string’
# html_string.erb <h1><%= @title %></h1>
# api controller @html_string = render_to_string(:html_string)
This is especially useful if the html string is dynamic and complicated, as you can use partials.