Views & ERB Templates
ERB syntax, layouts, partials, helpers, form_with, link_to, content_for, yield
1What is the difference between ERB tags <%= %> and <% %> ?
What is the difference between ERB tags <%= %> and <% %> ?
回答
The <%= %> tag evaluates Ruby code and outputs the result to HTML, while <% %> executes code without displaying anything. For example, <%= @user.name %> displays the user's name, whereas <% if @user.admin? %> only executes the condition. This distinction is fundamental for controlling what appears in the rendered page.
2Which ERB tag allows adding a comment that will not be visible in the generated HTML?
Which ERB tag allows adding a comment that will not be visible in the generated HTML?
回答
The <%# %> tag allows adding comments in ERB templates that will not be included in the final HTML. Unlike HTML comments <!-- -->, these comments are completely ignored during rendering and never appear in the source code sent to the browser, which is useful for internal notes.
3Where is the default layout of a Rails application located?
Where is the default layout of a Rails application located?
回答
The default layout of a Rails application is located in app/views/layouts/application.html.erb. This file contains the common HTML structure for all pages, including head and body tags, and the yield call that indicates where specific view content will be inserted. Controllers can specify a different layout if needed.
What is the purpose of the yield keyword in a Rails layout?
How to render a partial named _header.html.erb in a Rails view?
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