render(options = {}, locals = {}, &block)
The primary options are:
:partial - See ActionView::PartialRenderer.
:file - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
:inline - Renders an inline template similar to how it's done in the controller.
:plain - Renders the text passed in out. Setting the content type as text/plain.
:html - Renders the HTML safe string passed in out, otherwise performs HTML escape on the string first. Setting the content type as text/html.
:body - Renders the text passed in, and inherits the content type of text/plain from ActionDispatch::Response object.
Specify layout
<%= render partial: "link_area", layout: "graybar" %>
Block
# users/index.html.erb
<%= render "shared/search_filters", search: @q do |form| %>
<p>
Name contains: <%= form.text_field :name_contains %>
</p>
<% end %>
#
# shared/_search_filters.html.erb
<%= form_with model: search do |form| %>
<h1>Search form:</h1>
<fieldset>
<%= yield form %>
</fieldset>
<p>
<%= form.submit "Search" %>
</p>
<% end %>
<%= render partial: "form", locals: {zone: @zone} %>
:as and :object options
By default, PartialRenderer uses the template name for the local name of the object passed into the template. These examples are effectively the same:
<%= render :partial => "contract", :locals => { :contract => @contract } %>
<%= render :partial => "contract" %>
By specifying the :as option we can change the way the local variable is named in the template. These examples are effectively the same:
<%= render :partial => "contract", :as => :agreement %>
<%= render :partial => "contract", :locals => { :agreement => @contract } %>
The :object option can be used to directly specify which object is rendered into the partial.
<%= render :partial => "contract", :object => @buyer %>
<%= render :partial => "contract", :locals => { :contact => @buyer } %>
The :object and :as options can be used together. We might have a partial which we have named genericly, such as ‘form’. Using :object and :as together helps us.
<%= render :partial => "form", :object => @contract, :as => :contract %>
<%= render :partial => "form", :locals => {:contract => @contract} %>
Collection
<%= render :partial => "ad", :collection => @ads %>
Also, you can specify a partial which will be render as a spacer between each element by passing partial name to :spacer_template.
<%= render :partial => "ad", :collection => @ads, :spacer_template => "ad_divider" %>
Rendering the default case
Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if you’re following its conventions for RecordIdentifier#partial_path.
# @account is an Account instance, so it uses the RecordIdentifier to replace
# <%= render :partial => "accounts/account", :locals => { :account => @account} %>
<%= render :partial => @account %>
# @posts is an array of Post instances, so it uses the RecordIdentifier to replace
# <%= render :partial => "posts/post", :collection => @posts %>
<%= render :partial => @posts %>
If you’re not going to be using any of the options like collections or layouts, you can also use the short-hand defaults of render to render partials. Examples:
# Instead of <%= render :partial => "account" %>
<%= render "account" %>
# Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
<%= render "account", :account => @buyer %>
# @account is an Account instance, so it uses the RecordIdentifier to replace
# <%= render :partial => "accounts/account", :locals => { :account => @account } %>
<%= render(@account) %>
# @posts is an array of Post instances, so it uses the RecordIdentifier to replace
# <%= render :partial => "posts/post", :collection => @posts %>
<%= render(@posts) %>
Question: some place says render will not accept additional local variables for the partial. But it seems I can pass multiple variables for render. New feature (Rails 6)?
<%= render 'record', table: @table, record: @record %>