This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

This cop makes sure that Ruby source files have snake_case names. Ruby scripts (i.e. source files with a shebang in the first line) are ignored.

Example:

# bad
lib/layoutManager.rb

anything/usingCamelCase

# good
lib/layout_manager.rb

anything/using_snake_case.rake

Checks that required_ruby_version of gemspec and TargetRubyVersion of .rubocop.yml are equal. Thereby, RuboCop to perform static analysis working on the version required by gemspec.

Example:

# When `TargetRubyVersion` of .rubocop.yml is `2.3`.

# bad
Gem::Specification.new do |spec|
  spec.required_ruby_version = '>= 2.2.0'
end

# bad
Gem::Specification.new do |spec|
  spec.required_ruby_version = '>= 2.4.0'
end

# good
Gem::Specification.new do |spec|
  spec.required_ruby_version = '>= 2.3.0'
end

# good
Gem::Specification.new do |spec|
  spec.required_ruby_version = '>= 2.3'
end

# good
Gem::Specification.new do |spec|
  spec.required_ruby_version = ['>= 2.3.0', '< 2.5.0']
end

Checks that brackets used for array literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that array literals have
# surrounding space.

# bad
array = [a, b, c, d]

# good
array = [ a, b, c, d ]

Example: EnforcedStyle: no_space

# The `no_space` style enforces that array literals have
# no surrounding space.

# bad
array = [ a, b, c, d ]

# good
array = [a, b, c, d]

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# array brackets, with the exception that successive left
# or right brackets are collapsed together in nested arrays.

# bad
array = [ a, [ b, c ] ]

# good
array = [ a, [ b, c ]]

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

This cop enforces the consistent usage of %-literal delimiters.

Specify the 'default' key to set all preferred delimiters at once. You can continue to specify individual preferred delimiters to override the default.

Example:

# Style/PercentLiteralDelimiters:
#   PreferredDelimiters:
#     default: '[]'
#     '%i':    '()'

# good
%w[alpha beta] + %i(gamma delta)

# bad
%W(alpha #{beta})

# bad
%I(alpha beta)

Checks that block braces have or don't have a space before the opening brace depending on configuration.

Example:

# bad
foo.map{ |a|
  a.bar.to_s
}

# good
foo.map { |a|
  a.bar.to_s
}

Checks for unnecessary additional spaces inside the delimiters of %i/%w/%x literals.

Example:

# good
%i(foo bar baz)

# bad
%w( foo bar baz )

# bad
%x(  ls -l )