How to add sub commands in my SPFX List View Command Set command

Question

My SPFX contains extension that adds two commands in Document List:

Elements.xml:

<CustomAction
      Title="My Commands"
      RegistrationId="101"
      RegistrationType="List"
      Location="ClientSideExtension.ListViewCommandSet"
      ClientSideComponentId="887c888e-abd4-4552-ad51-7ff1d526e3ba">
  </CustomAction>

MyCommandsSet.manifest.json

{
  "$schema": "https://developer.microsoft.com/json-schemas/spfx/command-set-extension-manifest.schema.json",

  "id": "4d7c888e-abd4-4552-ad51-7ff1d526e3ba",
  "alias": "MyCommandsSet",
  "componentType": "Extension",
  "extensionType": "ListViewCommandSet",

  "version": "*",
  "manifestVersion": 2,

  "requiresCustomScript": false,

  "items": {
    "COMMAND_1": {
      "title": { "default": "My Command 1" },
      "type": "command"
    },
    "COMMAND_2": {
      "title": { "default": "My Command 2" },
      "type": "command"
    }
  }
}

These two commands are placed in both Command Bar and Context Menu. But it's not that I want. How can I add one command like submenu with these two commands in it? So I want to have one command (e.g. "My Commands") that will work as menu and show two sub-commands: "My Command 1" and "My Command 2".

Example:

Answer 1

Check similar thread below.

How to group the list command using SPFx ListView Command Set extension?

As a workaround, we can use PnP PowerShell to achieve it.

Example:

customaction_modern_editcontrolblock.xml

<pnp:ProvisioningTemplate ID="CommandUIRibbonSamples" Version="1" xmlns:pnp="http://schemas.dev.office.com/PnP/2015/12/ProvisioningSchema">
  <pnp:CustomActions>
    <pnp:SiteCustomActions>
      <pnp:CustomAction Name="CA_4" Description="ca 4" Location="CommandUI.Ribbon" RegistrationType="List" RegistrationId="101" Title="CA 4 Title" Sequence="6000" Enabled="true">
        <pnp:CommandUIExtension>
          <CommandUIDefinitions>
            <CommandUIDefinition Location="Ribbon.Documents.Copies.Controls._children">
              <Button
                Id="Ribbon.Documents.Copies.OfficeDevPnPDownloadAll"
                Command="OfficeDevPnP.Cmd.DownloadAll"
                Image16by16="/_layouts/15/images/sharepointfoundation16.png"
                LabelText="Download All"
                Description="Download all files separately"
                ToolTipTitle="Download All"
                ToolTipDescription="Download all files separately"
                TemplateAlias="o1"
                Sequence="15"/>
            </CommandUIDefinition>
          </CommandUIDefinitions>
          <CommandUIHandlers>
            <CommandUIHandler
              Command="OfficeDevPnP.Cmd.DownloadAll"
              CommandAction="https://contoso.azurewebsites.net/pages/index.aspx" />
          </CommandUIHandlers>
        </pnp:CommandUIExtension>
      </pnp:CustomAction>
      <pnp:CustomAction Name="CA_6" Description="ca 6" Location="CommandUI.Ribbon" RegistrationType="ContentType" RegistrationId="0x0101" Title="CA 6 Title" Sequence="5000" Enabled="true">
        <pnp:CommandUIExtension>
            <CommandUIDefinitions>
              <CommandUIDefinition Location="Ribbon.Tabs._children">
                <Tab Id="Custom Tab" Title="Custom Tab" Description="Custom Tab">
                  <Scaling Id="Custom Tab.Scaling">
                    <MaxSize Id="Custom Group.Scaling.MaxSize" GroupId="Custom Group" Size="TwoLarge" />
                    <MaxSize Id="Custom Group 2.Scaling.MaxSize" GroupId="Custom Group 2" Size="OneLarge" />
                    <Scale Id="Custom Group.Scaling.Scale" GroupId="Custom Group" Size="TwoLarge" />
                    <Scale Id="Custom Group 2.Scaling.Scale" GroupId="Custom Group 2" Size="OneLarge" />
                  </Scaling>
                  <Groups Id="Custom Tab.Groups">
                    <Group Id="Custom Group 2" Title="Custom Group 2" Description="Custom Group 2" Sequence="7888" Template="Ribbon.Templates.OneLarge">
                      <Controls Id="Custom Group 2.Controls">
                        <Button Id="CustomButton3" LabelText="Custom Button 3" Image16by16="/_layouts/15/images/attach16.png" Image32by32="/_layouts/15/images/attach16.png" ToolTipTitle="Custom Button 3" ToolTipDescription="Custom Button 3" Command="CustomButton3.Command" TemplateAlias="c3" />
                      </Controls>
                    </Group>
                    <Group Id="Custom Group" Title="Custom Group 1" Description="Custom Group 1" Sequence="10000" Template="Ribbon.Templates.TwoLarge">
                      <Controls Id="Custom Group 1.Controls">
                        <Button Id="CustomButton1" LabelText="Custom Button 1" Image16by16="/_layouts/15/images/itslidelibrary.png" Image32by32="/_layouts/15/images/itslidelibrary.png" ToolTipTitle="Custom Button 1" ToolTipDescription="Custom Button 1" Command="CustomButton1.Command" TemplateAlias="c1" />
                        <Button Id="CustomButton2" LabelText="Custom Button 2" Image16by16="/_layouts/15/images/dldsln16.png" Image32by32="/_layouts/15/images/dldsln16.png" ToolTipTitle="Custom Button 2" ToolTipDescription="Custom Button 2" Command="CustomButton2.Command" TemplateAlias="c2" />
                      </Controls>
                    </Group>
                  </Groups>
                </Tab>
              </CommandUIDefinition>
              <CommandUIDefinition Location="Ribbon.Templates._children">
                <GroupTemplate Id="Ribbon.Templates.TwoLarge">
                  <Layout Title="TwoLarge" LayoutTitle="TwoLarge"> 
                    <Section Alignment="Top" Type="OneRow"> 
                      <Row> 
                        <ControlRef DisplayMode="Large" TemplateAlias="c1" /> 
                        <ControlRef DisplayMode="Large" TemplateAlias="c2" /> 
                      </Row> 
                    </Section> 
                  </Layout> 
                </GroupTemplate>
              </CommandUIDefinition>
              <CommandUIDefinition Location="Ribbon.Templates._children">
                <GroupTemplate Id="Ribbon.Templates.OneLarge">
                  <Layout Title="OneLarge" LayoutTitle="OneLarge"> 
                    <Section Alignment="Top" Type="OneRow"> 
                      <Row> 
                        <ControlRef DisplayMode="Large" TemplateAlias="c3" /> 
                      </Row> 
                    </Section> 
                  </Layout> 
                </GroupTemplate>
              </CommandUIDefinition>
            </CommandUIDefinitions>
            <CommandUIHandlers>
              <CommandUIHandler Command="CustomButton1.Command" CommandAction="https://contoso.azurewebsites.net/pages/index.aspx" />
              <CommandUIHandler Command="CustomButton2.Command" CommandAction="http://www.bing.com" />
              <CommandUIHandler Command="CustomButton3.Command" CommandAction="http://dev.office.com/sharepoint" />
            </CommandUIHandlers>
        </pnp:CommandUIExtension>
      </pnp:CustomAction>
    </pnp:SiteCustomActions>
  </pnp:CustomActions>
</pnp:ProvisioningTemplate>

PnP PowerShell

# Connect to a previously created Modern Site
$cred = Get-Credential
Connect-PnPOnline -Url https://tenant.sharepoint.com/sites/team -Credentials $cred

# Apply the PnP provisioning template
Apply-PnPProvisioningTemplate -Path c:\temp\customaction_modern_editcontrolblock.xml -Handlers CustomActions

More information is here:

Customizing "modern" lists and libraries