Issue #21346 has been updated by maxfelsher (Max Felsher). I like this idea, but I'm concerned about the same method returning `self` in one case and a new string in another. It seems like it'd be easier to reason about if it either always returned a new string or always affected the original object. Or if there's a bang version, it would be consistent with `chomp`, `sub`, etc., for the non-bang version to always return a new string and the bang version to always affect the original object. Apologies if I'm missing something! ---------------------------------------- Feature #21346: Introduce `String#ensure_suffix` https://bugs.ruby-lang.org/issues/21346#change-113576 * Author: matheusrich (Matheus Richard) * Status: Open ---------------------------------------- ## Problem Ensuring a string has a specific suffix or prefix is a common operation in many applications. Bundler itself uses it: https://github.com/rubygems/rubygems/blob/d409ec8b5fc647fabe30e37e17cd1ea857... Here are [GitHub search](https://github.com/search) queries that might find this pattern in other places: 1. for Ruby: `/end(?:s)?_with\?\(['"].*['"]\) \?/ lang:ruby -is:fork` 1. for Crystal (a language very similar to Ruby): `/ends_with\?\(['"].*['"]\) \?/ lang:crystal -is:fork` ## Suggested solution I believe Ruby would benefit from having a first-class method for this purpose. I suggest the `String#ensure_suffix` and `String#ensure_prefix` methods. I think these names are intuitive enough (here are 2 examples of people using `ensure` for this purpose ([1](https://github.com/boltops-tools/ufo/blob/796104fdb89163d09a58fad42add697923...), [2](https://github.com/mumuki/mumuki-domain/blob/6194089d82b1a0c8805ecba98e006de...))). I've gone ahead and implemented `String#ensure_suffix` in a [pull request](https://github.com/ruby/ruby/pull/13366) but the suggested behavior is this: ```rb "Hell".ensure_suffix("o!") # => "Hello!" "Hello!".ensure_suffix("o!") # => "Hello!" s = "Hello!" s.ensure_suffix("!").equal?(s) # => true # returns same object if already suffixed ``` -- https://bugs.ruby-lang.org/