Fork me on GitHub

Project Notes

Using with_defaults

About the reverse_merge and with_defaults Hash mixins from Rails


A great little article from Andy Croll: For clarity merging hashes use with_defaults

I’ve used reverse_merge quite a bit, but the semantics of with_defaults are very nice IMHO.

params = { a: 'value of a', b: 'value of b' }
defaults = { a: 'default value of a', b: 'default value of b', c: 'default value of c' }
=> { a: 'value of a', b: 'value of b', c: 'default value of c' }

These functionas are available if running Rails. To use in other ruby projects, add ‘activesupport’ gem to your project and require core activesupport:

require 'active_support'
require 'active_support/core_ext'

Example Test

See a simepl test in test_with_defaults.rb:

$ ./test_with_defaults.rb
Run options: --seed 24687

# Running:


Finished in 0.001573s, 635.7279 runs/s, 635.7279 assertions/s.

1 runs, 1 assertions, 0 failures, 0 errors, 0 skips

Credits and References

About LCK#269 ruby
Project Source on GitHub Return to the Project Catalog

This page is a web-friendly rendering of my project notes shared in the LittleCodingKata GitHub repository.

LittleCodingKata is my collection of programming exercises, research and code toys broadly spanning things that relate to programming and software development (languages, frameworks and tools).

These range from the trivial to the complex and serious. Many are inspired by existing work and I'll note credits and references where applicable. The focus is quite scattered, as I variously work on things new and important in the moment, or go back to revisit things from the past.

This is primarily a personal collection for my own edification and learning, but anyone who stumbles by is welcome to borrow, steal or reference the work here. And if you spot errors or issues I'd really appreciate some feedback - create an issue, send me an email or even send a pull-request.