co-locate our tests files with the file or group of files they are testing
⇒ we can see immediately that the module is tested
State
Localize your state
Maintainability
Performant ⇒ e-render a lot fewer components
"Reusable" utility files
"Huh... I'll bet a lot of people could use this." ⇒ the component uses that util function is deleted, but the utility you wrote is out of sight, out of mind and it remains
My Thoughts
I will try to practice "Place code as close to where it's relevant as possible"
I often have the situation where separating a function to utilities. I will think carefully from next time