Class LocalStorageCommandHandler

GoJS® Diagramming Components
version 3.0.2
by Northwoods Software®

This is an extension and not part of the main GoJS library. Note that the API for this class may change at any time. If you intend to use an extension in production, you should copy the code to your own source directory. See the Extensions intro page for more information.


This CommandHandler class uses localStorage as the repository for the clipboard, rather than an in-memory global variable. It requires that the go.Diagram.model be serializable and deserializable using go.Model.toJson and go.Model.fromJson.

The copyToClipboard and pasteFromClipboard functions fall back to using the standard definitions if there are any errors calling Storage.getItem or Storage.setItem.

Typical usage:

  new go.Diagram("myDiagramDiv",
commandHandler: new LocalStorageCommandHandler(),


  myDiagram.commandHandler = new LocalStorageCommandHandler();

If you want to experiment with this extension, try the Local Storage Commands sample.






  • Makes a copy of the given collection of go.Parts and stores it as JSON in LocalStorage.


    Returns void

  • If LocalStorage holds JSON for a collection of go.Parts, and if the go.Model.dataFormat matches that stored in the clipboard, this makes a copy of the clipboard's parts and adds the copies to this go.Diagram.

    Returns Set<Part>

    a collection of newly pasted go.Parts