Some code editors, such as WebStorm, have an option to auto-save when the editor loses focus. I've searched for an option like this in the Atom Editor but haven't found anything yet.
Does the Atom Editor have a setting that allows for auto-save of edited files when it loses focus? If so, where can this be set? If not, how would one go about writing a plug-in that does that?
Yes there is auto save package. You can enable autosave in package settings.