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require 'active_support/core_ext/module'
require 'action_view/model_naming'
module ActionView
# RecordIdentifier encapsulates methods used by various ActionView helpers
# to associate records with DOM elements.
#
# Consider for example the following code that displays the body of a post:
#
# <%= div_for(post) do %>
# <%= post.body %>
# <% end %>
#
# When +post+ is a new, unsaved ActiveRecord::Base intance, the resulting HTML
# is:
#
# <div id="new_post" class="post">
# </div>
#
# When +post+ is a persisted ActiveRecord::Base instance, the resulting HTML
# is:
#
# <div id="post_42" class="post">
# What a wonderful world!
# </div>
#
# In both cases, the +id+ and +class+ of the wrapping DOM element are
# automatically generated, following naming conventions encapsulated by the
# RecordIdentifier methods #dom_id and #dom_class:
#
# dom_id(Post.new) # => "new_post"
# dom_class(Post.new) # => "post"
# dom_id(Post.find 42) # => "post_42"
# dom_class(Post.find 42) # => "post"
#
# Note that these methods do not strictly require +Post+ to be a subclass of
# ActiveRecord::Base.
# Any +Post+ class will work as long as its instances respond to +to_key+
# and +model_name+, given that +model_name+ responds to +param_key+.
# For instance:
#
# class Post
# attr_accessor :to_key
#
# def model_name
# OpenStruct.new param_key: 'post'
# end
#
# def self.find(id)
# new.tap { |post| post.to_key = [id] }
# end
# end
module RecordIdentifier
extend self
extend ModelNaming
include ModelNaming
JOIN = '_'.freeze
NEW = 'new'.freeze
# The DOM class convention is to use the singular form of an object or class.
#
# dom_class(post) # => "post"
# dom_class(Person) # => "person"
#
# If you need to address multiple instances of the same class in the same view, you can prefix the dom_class:
#
# dom_class(post, :edit) # => "edit_post"
# dom_class(Person, :edit) # => "edit_person"
def dom_class(record_or_class, prefix = nil)
singular = model_name_from_record_or_class(record_or_class).param_key
prefix ? "#{prefix}#{JOIN}#{singular}" : singular
end
# The DOM id convention is to use the singular form of an object or class with the id following an underscore.
# If no id is found, prefix with "new_" instead.
#
# dom_id(Post.find(45)) # => "post_45"
# dom_id(Post.new) # => "new_post"
#
# If you need to address multiple instances of the same class in the same view, you can prefix the dom_id:
#
# dom_id(Post.find(45), :edit) # => "edit_post_45"
# dom_id(Post.new, :custom) # => "custom_post"
def dom_id(record, prefix = nil)
if record_id = record_key_for_dom_id(record)
"#{dom_class(record, prefix)}#{JOIN}#{record_id}"
else
dom_class(record, prefix || NEW)
end
end
protected
# Returns a string representation of the key attribute(s) that is suitable for use in an HTML DOM id.
# This can be overwritten to customize the default generated string representation if desired.
# If you need to read back a key from a dom_id in order to query for the underlying database record,
# you should write a helper like 'person_record_from_dom_id' that will extract the key either based
# on the default implementation (which just joins all key attributes with '_') or on your own
# overwritten version of the method. By default, this implementation passes the key string through a
# method that replaces all characters that are invalid inside DOM ids, with valid ones. You need to
# make sure yourself that your dom ids are valid, in case you overwrite this method.
def record_key_for_dom_id(record)
key = convert_to_model(record).to_key
key ? key.join(JOIN) : key
end
end
end
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