Everything that you typed in the console are automatically saved in application logs. After you restart Slicer, in menu choose: Help / Report a bug, select any of the previous session from the list, and you’ll see the commands you typed.
Previously, when I was not developing a module, I’ve been mostly copy-pasting from editors. However, now there is a new, very nice alternative: using Slicer from Jupyter notebooks. Instead of manual copy-pasting, you enter your code as small blocks of text, which is very easy to edit and re-run.