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Versions: 19
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Contents
# frozen_string_literal: true
module ArLazyPreload
# This class is responsible for building association subtrees from a given association tree
# For instance, given a following tree `[:users, { users: :comments }]`,
# #subtree_for will build a subtree `[:comments]` when :users argument is passed
class AssociationTreeBuilder
attr_reader :association_tree
def initialize(association_tree)
@association_tree =
case association_tree
when Array
association_tree
when Hash
[association_tree]
else
raise ArgumentError, "unexpected association_tree with class #{association_tree.class}"
end.select { |node| node.is_a?(Hash) }
end
def subtree_for(association)
subtree_cache[association]
end
private
def subtree_cache
@subtree_cache ||= Hash.new do |hash, association|
hash[association] = association_tree.flat_map { |node| node[association] }
end
end
end
end
Version data entries
19 entries across 19 versions & 1 rubygems