class RuboCop::Cop::Rails::IndexBy

This cop looks for uses of `each_with_object({}) { … }`, `map { … }.to_h`, and `Hash[map { … }]` that are transforming an enumerable into a hash where the values are the original elements. Rails provides the `index_by` method for this purpose.

@example

# bad
[1, 2, 3].each_with_object({}) { |el, h| h[foo(el)] = el }
[1, 2, 3].to_h { |el| [foo(el), el] }
[1, 2, 3].map { |el| [foo(el), el] }.to_h
Hash[[1, 2, 3].collect { |el| [foo(el), el] }]

# good
[1, 2, 3].index_by { |el| foo(el) }

Private Instance Methods

new_method_name() click to toggle source
# File lib/rubocop/cop/rails/index_by.rb, line 59
def new_method_name
  'index_by'
end