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Class: RuboCop::Cop::Style::HashTransformValues

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/hash_transform_values.rb

Overview

Looks for uses of _.each_with_object({}) {…​}, \_.map {…​}.to_h, and Hash[\_.map {…​}] that are actually just transforming the values of a hash, and tries to use a simpler & faster call to transform_values instead.

Examples:

# bad
{a: 1, b: 2}.each_with_object({}) { |(k, v), h| h[k] = foo(v) }
Hash[{a: 1, b: 2}.collect { |k, v| [k, foo(v)] }]
{a: 1, b: 2}.map { |k, v| [k, v * v] }.to_h
{a: 1, b: 2}.to_h { |k, v| [k, v * v] }

# good
{a: 1, b: 2}.transform_values { |v| foo(v) }
{a: 1, b: 2}.transform_values { |v| v * v }

Cop Safety Information:

  • This cop is unsafe, as it can produce false positives if we are transforming an enumerable of key-value-like pairs that isn’t actually a hash, e.g.: [[k1, v1], [k2, v2], …​]

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::HashTransformMethod - Included

RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::TargetRubyVersion - Extended

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::HashTransformMethod - Included

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#extract_captures(match) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/hash_transform_values.rb', line 82

def extract_captures(match)
  val_argname, key_body_expr, val_body_expr = *match
  Captures.new(val_argname, val_body_expr, key_body_expr)
end

#new_method_name (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/hash_transform_values.rb', line 87

def new_method_name
  'transform_values'
end

#on_bad_each_with_object(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/hash_transform_values.rb', line 34

def_node_matcher :on_bad_each_with_object, <<~PATTERN
  (block
    (call !#array_receiver? :each_with_object (hash))
    (args
      (mlhs
        (arg _key)
        (arg $_))
      (arg _memo))
    (call (lvar _memo) :[]= $(lvar _key) $!`_memo))
PATTERN

#on_bad_hash_brackets_map(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/hash_transform_values.rb', line 46

def_node_matcher :on_bad_hash_brackets_map, <<~PATTERN
  (send
    (const _ :Hash)
    :[]
    (block
      (call !#array_receiver? {:map :collect})
      (args
        (arg _key)
        (arg $_))
      (array $(lvar _key) $_)))
PATTERN

#on_bad_map_to_h(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/hash_transform_values.rb', line 59

def_node_matcher :on_bad_map_to_h, <<~PATTERN
  (call
    (block
      (call !#array_receiver? {:map :collect})
      (args
        (arg _key)
        (arg $_))
      (array $(lvar _key) $_))
    :to_h)
PATTERN

#on_bad_to_h(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/hash_transform_values.rb', line 71

def_node_matcher :on_bad_to_h, <<~PATTERN
  (block
    (call !#array_receiver? :to_h)
    (args
      (arg _key)
      (arg $_))
    (array $(lvar _key) $_))
PATTERN