Class: RuboCop::Cop::Metrics::CollectionLiteralLength

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/metrics/collection_literal_length.rb

Overview

Checks for literals with extremely many entries. This is indicative of configuration or data that may be better extracted somewhere else, like a database, fetched from an API, or read from a non-code file (CSV, JSON, YAML, etc.).

Examples:

# bad
# Huge Array literal
[1, 2, '...', 999_999_999]

# bad
# Huge Hash literal
{ 1 => 1, 2 => 2, '...' => '...', 999_999_999 => 999_999_999}

# bad
# Huge Set "literal"
Set[1, 2, '...', 999_999_999]

# good
# Reasonably sized Array literal
[1, 2, '...', 10]

# good
# Reading huge Array from external data source
# File.readlines('numbers.txt', chomp: true).map!(&:to_i)

# good
# Reasonably sized Hash literal
{ 1 => 1, 2 => 2, '...' => '...', 10 => 10}

# good
# Reading huge Hash from external data source
CSV.foreach('numbers.csv', headers: true).each_with_object({}) do |row, hash|
  hash[row["key"].to_i] = row["value"].to_i
end

# good
# Reasonably sized Set "literal"
Set[1, 2, '...', 10]

# good
# Reading huge Set from external data source
SomeFramework.config_for(:something)[:numbers].to_set

Constant Summary collapse

MSG = 
'Avoid hard coding large quantities of data in code. ' \
'Prefer reading the data from an external source.'
RESTRICT_ON_SEND = 
[:[]].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #begin_investigation, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#on_array(node) ⇒ Object Also known as: on_hash 



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# File 'lib/rubocop/cop/metrics/collection_literal_length.rb', line 55

def on_array(node)
  add_offense(node) if node.children.length >= collection_threshold
end

#on_index(node) ⇒ Object 



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# File 'lib/rubocop/cop/metrics/collection_literal_length.rb', line 60

def on_index(node)
  add_offense(node) if node.arguments.length >= collection_threshold
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/metrics/collection_literal_length.rb', line 64

def on_send(node)
  on_index(node) if node.method?(:[])
end