class RuboCop::Cop::Style::HashTransformKeys
Looks for uses of ‘_.each_with_object({}) {…}`, `_.map {…}.to_h`, and `Hash[_.map {…}]` that are actually just transforming the keys of a hash, and tries to use a simpler & faster call to `transform_keys` instead. It should only be enabled on Ruby version 2.5 or newer. (`transform_keys` was added in Ruby 2.5.)
@safety
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], ...]`
@example
# bad {a: 1, b: 2}.each_with_object({}) { |(k, v), h| h[foo(k)] = v } Hash[{a: 1, b: 2}.collect { |k, v| [foo(k), v] }] {a: 1, b: 2}.map { |k, v| [k.to_s, v] }.to_h {a: 1, b: 2}.to_h { |k, v| [k.to_s, v] } # good {a: 1, b: 2}.transform_keys { |k| foo(k) } {a: 1, b: 2}.transform_keys { |k| k.to_s }
Private Instance Methods
extract_captures(match)
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# File lib/rubocop/cop/style/hash_transform_keys.rb, line 84 def extract_captures(match) key_argname, key_body_expr, val_body_expr = *match Captures.new(key_argname, key_body_expr, val_body_expr) end
new_method_name()
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# File lib/rubocop/cop/style/hash_transform_keys.rb, line 89 def new_method_name 'transform_keys' end