Class: RuboCop::Cop::Performance::SelectMap

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, TargetRubyVersion, Base
Instance Chain: self, RangeHelp, Base
Inherits:	Base Object Base RuboCop::Cop::Performance::SelectMap
Defined in:	lib/rubocop/cop/performance/select_map.rb

Overview

In Ruby 2.7, Enumerable#filter_map has been added.

This cop identifies places where select.map can be replaced by filter_map.

Examples:

# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }

Constant Summary

MSG =
# File 'lib/rubocop/cop/performance/select_map.rb', line 24
```
'Use `filter_map` instead of `%<method_name>s.map`.'
```
RESTRICT_ON_SEND =
# File 'lib/rubocop/cop/performance/select_map.rb', line 25
```
%i[select filter].freeze
```

Instance Method Summary

#on_csend(node)

Alias for #on_send.
#on_send(node) (also: #on_csend)
#map_method_candidate(node) private
#offense_range(node, map_method) private

Instance Method Details

#map_method_candidate(node) (private)

[ GitHub ]

# File 'lib/rubocop/cop/performance/select_map.rb', line 41


def map_method_candidate(node)
  return unless (parent = node.parent)

  if parent.block_type? && parent.parent&.call_type?
    parent.parent
  elsif parent.call_type?
    parent
  end
end

#offense_range(node, map_method) (private)

[ GitHub ]

# File 'lib/rubocop/cop/performance/select_map.rb', line 51


def offense_range(node, map_method)
  range_between(node.loc.selector.begin_pos, map_method.source_range.end_pos)
end

#on_csend(node)

Alias for #on_send.

[ GitHub ]

# File 'lib/rubocop/cop/performance/select_map.rb', line 37


alias on_csend on_send

#on_send(node) Also known as: #on_csend

[ GitHub ]

# File 'lib/rubocop/cop/performance/select_map.rb', line 27


def on_send(node)
  return if (first_argument = node.first_argument) && !first_argument.block_pass_type?
  return unless (send_node = map_method_candidate(node))
  return unless send_node.method?(:map)

  map_method = send_node.parent&.block_type? ? send_node.parent : send_node

  range = offense_range(node, map_method)
  add_offense(range, message: format(MSG, method_name: node.method_name))
end