Rails 4 - passing variable to partial
From the Rails api on PartialRender:
Rendering the default case
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.to_partial_path returns 'accounts/account', so it can be used to replace:
# <%= render partial: "accounts/account", locals: { account: @account} %>
<%= render @account %>
# @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
# that's why we can replace:
# <%= render partial: "posts/post", collection: @posts %>
<%= render @posts %>
So, you can use pass a local variable size
to render as follows:
<%= render @users, size: 50 %>
and then use it in the _user.html.erb
partial:
<li>
<%= gravatar_for user, size: size %>
<%= link_to user.name, user %>
</li>
Note that size: size
is equivalent to :size => size
.
You need the full render partial syntax if you are passing locals
<%= render @users, :locals => {:size => 30} %>
Becomes
<%= render :partial => 'users', :collection => @users, :locals => {:size => 30} %>
Or to use the new hash syntax
<%= render partial: 'users', collection: @users, locals: {size: 30} %>
Which I think is much more readable