Pattern: Missing use of delete_prefix('prefix')
Issue: -
In Ruby 2.5, String#delete_prefix has been added.
This rule identifies places where gsub(/\Aprefix/, '') and sub(/\Aprefix/, '') can be replaced by delete_prefix('prefix').
This rule has SafeMultiline configuration option that true by default because ^prefix is unsafe as it will behave incompatible with delete_prefix for receiver is multi-line string.
The delete_prefix('prefix') method is faster than gsub(/\Aprefix/, '').
# bad
str.gsub(/\Aprefix/, '')
str.gsub!(/\Aprefix/, '')
str.sub(/\Aprefix/, '')
str.sub!(/\Aprefix/, '')
# good
str.delete_prefix('prefix')
str.delete_prefix!('prefix')