Today I Learned

TIL, 2017-04-02, assert_valid_keys

  • Mass move: mv _posts/*.md _posts/programming.
  • Just use update_attributes! and create! instead of update_attributes and create, if only to avoid silent failures. The update_attributes will work if you are doing a valid? later. Reference
  • Another ActiveSupport gem: assert_valid_keys.
  • rack-mini-profiler.

Benefits of Testing

  • It is a way to document what your code does.
  • Sooner or later, you will forget what your code actually did, it is like a mental reminder of why your code is like this or like that.
  • It is a way to ensure sanity when trying to refactor a class. Show: Tenants::CreateService.
  • It is a way to ensure that everything still works when trying to optimize something in your Rails code. Show: An example of ensuring that n+1 queries will be sped up. Reference
  • It is just a good practice to do. You
  • Small thing: You figure out what is memoized or not. BTW small things like this are impora


  • You are like learning a new programming language.

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