class RuboCop::Cop::Style::EachWithObject
This cop looks for inject / reduce calls where the passed in object is returned at the end and so could be replaced by each_with_object without the need to return the object at the end.
However, we can't replace with each_with_object if the accumulator parameter is assigned to within the block.
@example
# bad [1, 2].inject({}) { |a, e| a[e] = e; a } # good [1, 2].each_with_object({}) { |e, a| a[e] = e }
Constants
- METHODS
- MSG
Public Instance Methods
on_block(node)
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# File lib/rubocop/cop/style/each_with_object.rb, line 26 def on_block(node) each_with_object_candidate?(node) do |method, args, body| _, method_name, method_arg = *method return if simple_method_arg?(method_arg) return_value = return_value(body) return unless return_value return unless first_argument_returned?(args, return_value) return if accumulator_param_assigned_to?(body, args) add_offense(node, location: method.loc.selector, message: format(MSG, method_name)) end end
Private Instance Methods
accumulator_param_assigned_to?(body, args)
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if the accumulator parameter is assigned to in the block, then we can't convert to each_with_object
# File lib/rubocop/cop/style/each_with_object.rb, line 66 def accumulator_param_assigned_to?(body, args) first_arg, = *args accumulator_var, = *first_arg body.each_descendant.any? do |n| next unless n.assignment? lhs, _rhs = *n lhs.equal?(accumulator_var) end end
autocorrect(node)
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rubocop:disable Metrics/AbcSize
# File lib/rubocop/cop/style/each_with_object.rb, line 44 def autocorrect(node) lambda do |corrector| corrector.replace(node.send_node.loc.selector, 'each_with_object') first_arg, second_arg = *node.arguments corrector.replace(first_arg.loc.expression, second_arg.source) corrector.replace(second_arg.loc.expression, first_arg.source) return_value = return_value(node.body) corrector.remove(return_value.loc.expression) end end
first_argument_returned?(args, return_value)
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# File lib/rubocop/cop/style/each_with_object.rb, line 85 def first_argument_returned?(args, return_value) first_arg, = *args accumulator_var, = *first_arg return_var, = *return_value accumulator_var == return_var end
return_value(body)
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# File lib/rubocop/cop/style/each_with_object.rb, line 78 def return_value(body) return unless body return_value = body.begin_type? ? body.children.last : body return_value if return_value && return_value.lvar_type? end
simple_method_arg?(method_arg)
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rubocop:endable Metrics/AbcSize
# File lib/rubocop/cop/style/each_with_object.rb, line 60 def simple_method_arg?(method_arg) method_arg && method_arg.basic_literal? end