VisioOnline: Application object example. https://dev.office.com/reference/add-ins/visio/application.

application.js

Visio.run(function (ctx) { 
    var application = ctx.document.application;
    application.showToolbars = false;
    return ctx.sync();
}).catch(function(error) {
        console.log("Error: " + error);
        if (error instanceof OfficeExtension.Error) {
            console.log("Debug info: " + JSON.stringify(error.debugInfo));
        }
});