Sorry if it’s a common knowledge, but it’s something I just learned and wanted to share.
I’ve seen that mind-blowing demo of hot-reload in production recently presented by Chris. So I asked if we could have something like that in development as well: Jakub Skałecki 🚀 #buildinpublic on X: "Hey @chris_mccord could we have this in development? 🧐 Right now state is not preserved across hot reloads" / X
It turns out, it’s there already! In your dev.exs Endpoint config add live_reload: notify section and update live_reload: patterns to match this:
# Watch static and templates for browser reloading.
config :my_app, MyAppWeb.Endpoint,
live_reload: [
notify: [
live_view: [
~r"lib/my_app_web/core_components.ex$",
~r"lib/my_app_web/(live|components)/.*(ex|heex)$"
]
],
patterns: [
~r"priv/static/(?!uploads/).*(js|css|png|jpeg|jpg|gif|svg)$",
~r"lib/my_app_web/controllers/.*(ex|heex)$"
]
]
Now when you update your live view code, your state will stay intact.
For me it’s a life-changer. I have to admit I wasted so much time without that feature 
Mostly when working with a bit more complex Live Views with forms or ephemeral state.
Did you know about it? Is it highlighted somewhere in the documentation / installation instructions but I just somehow missed it? 
