up-doc-usync-fallback.condition.ts

Custom Umbraco condition that permits when uSync is NOT installed. Used to control fallback sidebar group visibility.

What it does

Observes the Umbraco extension registry for menu type extensions. If usync.menu is found, the condition is NOT permitted (uSync is present, so UpDoc joins uSync’s group). If usync.menu is absent, the condition IS permitted (UpDoc creates its own “Synchronisation” sidebar group).

How it works

export class UpDocUsyncFallbackCondition
    extends UmbConditionBase<UmbConditionConfigBase>
    implements UmbExtensionCondition
{
    constructor(host, args) {
        super(host, args);
        this.observe(
            umbExtensionsRegistry.byType('menu'),
            (menus) => {
                const hasUsync = menus.some((m) => m.alias === 'usync.menu');
                this.permitted = !hasUsync;
            },
            'upDocUsyncCheck',
        );
    }
}

Key pattern: Extends UmbConditionBase (not UmbControllerBase). Uses this.observe() on the extension registry observable for reactive updates. The permitted setter automatically notifies the framework when the value changes.

Registered in

• manifest.ts as UpDoc.Condition.UsyncNotInstalled
• Applied to the fallback sectionSidebarApp (UpDoc.SidebarApp)

Used by

• manifest.ts — conditions array on the fallback sidebar group. When uSync IS installed, this condition blocks the fallback, preventing a duplicate “Synchronisation” header.

Future improvement

Currently hardcodes usync.menu as the check. A future enhancement would dynamically discover ANY existing “Synchronisation” sidebar group by label, making it package-agnostic. See planning/DYNAMIC_SIDEBAR_GROUP.md.