# did_you_mean [![Gem Version](https://badge.fury.io/rb/did_you_mean.svg)](https://rubygems.org/gems/did_you_mean) [![Build Status](https://travis-ci.org/yuki24/did_you_mean.svg?branch=master)](https://travis-ci.org/yuki24/did_you_mean) ## Installation Ruby 2.3 and later ships with this gem and it will automatically be `require`d when a Ruby process starts up. No special setup is required. ## Examples ### NameError #### Correcting a Misspelled Method Name ```ruby methosd # => NameError: undefined local variable or method `methosd' for main:Object # Did you mean? methods # method ``` #### Correcting a Misspelled Class Name ```ruby OBject # => NameError: uninitialized constant OBject # Did you mean? Object ``` #### Suggesting an Instance Variable Name ```ruby @full_name = "Yuki Nishijima" first_name, last_name = full_name.split(" ") # => NameError: undefined local variable or method `full_name' for main:Object # Did you mean? @full_name ``` #### Correcting a Class Variable Name ```ruby @@full_name = "Yuki Nishijima" @@full_anme # => NameError: uninitialized class variable @@full_anme in Object # Did you mean? @@full_name ``` ### NoMethodError ```ruby full_name = "Yuki Nishijima" full_name.starts_with?("Y") # => NoMethodError: undefined method `starts_with?' for "Yuki Nishijima":String # Did you mean? start_with? ``` ### KeyError ```ruby hash = {foo: 1, bar: 2, baz: 3} hash.fetch(:fooo) # => KeyError: key not found: :fooo # Did you mean? :foo ``` ## Experimental Features Aside from the basic features above, the `did_you_mean` gem comes with experimental features. They can be enabled by calling `require 'did_you_mean/experimental'`. Note that **these experimental features should never be enabled in production as they would impact Ruby's performance and use some unstable Ruby APIs.** ### Correcting an Instance Variable When It's Incorrectly Spelled ```ruby require 'did_you_mean/experimental' @full_name = "Yuki Nishijima" @full_anme.split(" ") # => NoMethodError: undefined method `split' for nil:NilClass # Did you mean? @full_name ``` ### Displaying a Warning When `initialize` is Incorrectly Spelled ```ruby require 'did_you_mean/experimental' class Person def intialize ... end end # => warning: intialize might be misspelled, perhaps you meant initialize? ``` ## Verbose Formatter This verbose formatter changes the error message format to take more lines/spaces so it'll be slightly easier to read the suggestions. This formatter can totally be used in any environment including production. ```ruby OBject # => NameError: uninitialized constant OBject # Did you mean? Object require 'did_you_mean/verbose' OBject # => NameError: uninitialized constant OBject # # Did you mean? Object # ``` ## Using the `DidYouMean::SpellChecker` If you need to programmatically find the closest matches to the user input, you could do so by re-using the `DidYouMean::SpellChecker` object. ```ruby spell_checker = DidYouMean::SpellChecker.new(dictionary: ['email', 'fail', 'eval']) spell_checker.correct('meail') # => ['email'] spell_checker.correct('afil') # => ['fail'] ``` ## Disabling `did_you_mean` Occasionally, you may want to disable the `did_you_mean` gem for e.g. debugging issues in the error object itself. You can disable it entirely by specifying `--disable-did_you_mean` option to the `ruby` command: ```bash $ ruby --disable-did_you_mean -e "1.zeor?" -e:1:in `
': undefined method `zeor?' for 1:Integer (NameError) ``` When you do not have direct access to the `ruby` command (e.g. `rails console`, `irb`), you could applyoptions using the `RUBYOPT` environment variable: ```bash $ RUBYOPT='--disable-did_you_mean' irb irb:0> 1.zeor? # => NoMethodError (undefined method `zeor?' for 1:Integer) ``` ### Getting the original error message Sometimes, you do not want to disable the gem entirely, but need to get the original error message without suggestions (e.g. testing). In this case, you could use the `#original_message` method on the error object: ```ruby no_method_error = begin 1.zeor? rescue NoMethodError => error error end no_method_error.message # => NoMethodError (undefined method `zeor?' for 1:Integer) # Did you mean? zero? no_method_error.original_message # => NoMethodError (undefined method `zeor?' for 1:Integer) ``` ## Benchmarking Performance is very important as the `did_you_mean` gem attempts to find the closest matches on the fly right after an exception is thrown. You could use the following rake tasks to get insights into how the gem performs: ```bash bundle exec rake benchmark:ips:jaro bundle exec rake benchmark:ips:levenshtein bundle exec rake benchmark:memory bundle exec rake benchmark:memory:jaro bundle exec rake benchmark:memory:levenshtein ``` **Be sure to always use `bundle exec` otherwise it will activate the pre-installed version of the `did_you_mean` gem rather than using what's in the `lib/`.** You could also use the [`benchmark-driver`](https://github.com/benchmark-driver/benchmark-driver) gem to know how each Ruby performs differently. ```bash bundle exec benchmark-driver benchmark/speed.yml --rbenv '2.6.0 --jit;2.6.0;2.5.3;truffleruby-1.0.0-rc10' --run-duration 30 ``` ## Contributing 1. Fork it (http://github.com/yuki24/did_you_mean/fork) 2. Create your feature branch (`git checkout -b my-new-feature`) 3. Commit your changes (`git commit -am 'Add some feature'`) 4. Make sure all tests pass (`bundle exec rake`) 5. Push to the branch (`git push origin my-new-feature`) 6. Create new Pull Request ## License Copyright (c) 2014-16 Yuki Nishijima. See MIT-LICENSE for further details.