ivar vs reader

ivar_vs_reader.md

Ruby: ivar vs readers

Spoiler alert: Readers win.

1. You don't rely on the instance state.
2. You've better protection againt typos. @ivar might not exist and nothing will fail ivar will complain.
3. They're easier to mock in specs in case you need to.
4. They properly wrap the state so that refactors are easier
5. they can be aliased
6. they can be alias_method_chained
7. no kittens will die
8. you can properly set their accessibility
9. etc.

When should I use ivars then?

1. When setting things on the constructor.
2. When memoizing stuff (and be careful).