With the advent of service operators and other web technologies, it is easier than ever to create web applications that work offline. Until now, the only way to edit Google Docs without being connected to the Internet was a Chrome extension. Starting today, it is no longer necessary.

Google announced today on the G Suite blog that the Docs, Sheets and Slides files could now be edited offline. as long as you mark the files (or the folders in which they are) for offline access when you are connected to the Internet. Any changes you make will be synchronized to Drive once you are reconnected.

This has not happened yet, but you can mark the files / folders for offline use by right-clicking on them and selecting "Available Offline". You can also quickly see which files are available locally with a new offline preview toggle at the top right of the Drive interface.