Why no helpers:
1. The scoping is weird and encourages bad patterns.
- You have access to the instance variables from whatever controller action happened to call the particular helper, but you can’t see that when writing the helper or in the view, so it’s very opaque. God forbid you actually USE the instance variables and you’ve now got these weird fragments of tightly coupled code between your controller and your template that quickly become hard to reason about.
- It’s better if you require that all helper methods be strictly functional, but in that case it’s still unintuitive because your methods are mixed into every view. This can lead to surprising name collisions and all kinds of other weirdness.
2. They’re not easy to test due to the issues above.
3. They’re weird to include elsewhere - for example if you want to reference in a model.
3. Most important: the principal value of common utility functions is to have the sort of “general purpose operations” defined in exactly one place, well tested, and then utilized everywhere else.
For all of these reasons you’re better off defining modules and using ‘module_function’ to make the methods directly accessible. Then you can just call the methods like ‘Utils.foo_bar()’ wherever you need them.
