A simple hot reload library for node.js that allows you to preserve application state across reloads.

DON'T USE IN PRODUCTION

Why not use nodemon or something similar?

They just reboot the whole application, meaning you lose its state.
This leads to the following problems.

1. This slows down reloads because state initialization is slow (connecting to the database, waiting for other services, etc.).
2. During development, it can be quite tedious to click buttons in the browser to get the app state suitable for testing a specific feature. Losing the app state forces you to repeat this process over and over again.

Installation

npm i @palisarbaro/stateful_hot_reload

Limitations

1. You should not relay on require cache
2. Works only with commonjs modules
3. main function shouldn't throw (otherwise saving invalid code can terminate node process)

Usage

1. You should have main function that accept boolean (true if reloaded, false if first run) and return shutdown function.
2. Do the state inititalization.
3. Only then call hot_reloading with main function.
4. Call watch to monitor changes. Or call do_reload manually when you need to reload.
   Both main and shutdown can be async

hot_reloading

Immidiatly calls main

do_reload

Stops the previous run by calling shutdown
Clears require cache, so you can reimport new version of code.
Calls main again.

watch

root - directory to watch
ignore - array of RegExp applied to full path of watched files (default is [/\/node_modules\//])
debounce_timeout - delay(milliseconds) before reload to prevent multiple reloads when saving multiple files (default is 100 ms)