class RuboCop::Cop::Performance::Size
This cop is used to identify usages of `count` on an `Array` and `Hash` and change them to `size`.
@example
# bad [1, 2, 3].count # bad {a: 1, b: 2, c: 3}.count # good [1, 2, 3].size # good {a: 1, b: 2, c: 3}.size # good [1, 2, 3].count { |e| e > 2 }
TODO: Add advanced detection of variables that could have been assigned to an array or a hash.
Constants
- MSG
Public Instance Methods
on_send(node)
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# File lib/rubocop/cop/performance/size.rb, line 28 def on_send(node) return unless eligible_node?(node) add_offense(node, location: :selector) end
Private Instance Methods
allowed_parent?(node)
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# File lib/rubocop/cop/performance/size.rb, line 52 def allowed_parent?(node) node && node.block_type? end
array?(node)
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# File lib/rubocop/cop/performance/size.rb, line 56 def array?(node) _, constant = *node.receiver node.array_type? || constant == :Array || node.method_name == :to_a end
autocorrect(node)
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# File lib/rubocop/cop/performance/size.rb, line 36 def autocorrect(node) ->(corrector) { corrector.replace(node.loc.selector, 'size') } end
eligible_node?(node)
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# File lib/rubocop/cop/performance/size.rb, line 40 def eligible_node?(node) return false unless node.method?(:count) && !node.arguments? eligible_receiver?(node.receiver) && !allowed_parent?(node.parent) end
eligible_receiver?(node)
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# File lib/rubocop/cop/performance/size.rb, line 46 def eligible_receiver?(node) return false unless node array?(node) || hash?(node) end
hash?(node)
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# File lib/rubocop/cop/performance/size.rb, line 62 def hash?(node) _, constant = *node.receiver node.hash_type? || constant == :Hash || node.method_name == :to_h end