on(event: "before-file-modification", listener: function): this
on(event: "after-file-modification", listener: function): this
registers the listener to be notified before a file is about to change. The change will be hold until all listeners returned promises are resolved. If any listener reject the promise the file modification action will be canceled.
registers the listener to be notified before a file is about to change. The change will be hold until all listeners returned promises are resolved. If any listener reject the promise the file modification action will be canceled.