When you have Flutter app performance problems, try Profile Mode

Today I learned that for several reasons, Flutter Debug mode may be significantly slower than Production mode. As just one reason, Debug mode is compiled using JIT while Production mode uses AOT. You can read more about the reasons on the Flutter UI Performance page.

A very important note on that page is that if you’re using a real hardware device (as opposed to an emulator), you can run your code in Profile mode like this:

A shell script to change between MacOS dark mode and light mode

If you want to create a shell script so you can change between MacOS dark mode and light mode from the Terminal (Unix) command line, put this source code in a file and name it something like dark:

osascript -e \
'tell application "System Events" to tell appearance preferences to set dark mode to not dark mode'

Then make that file executable, and make sure it’s on your PATH. Now you can type dark to toggle back and forth between dark mode and the regular light mode: