Feat v0.8.5 extension composability (#72)

Co-authored-by: Jeffrey Smith <jasafpro@gmail.com>
Co-committed-by: Jeffrey Smith <jasafpro@gmail.com>

src/js/sw/sdk/slots.js

@@ -15,6 +15,8 @@
 export function createSlots(emitFn) {
     /** @type {Map<string, Array<{id:string, component:Function, priority:number}>>} */
     const _registry = new Map();
+    /** @type {Map<string, string>|undefined} */
+    let _declarations;
 
     function _sort(arr) {
         arr.sort((a, b) => a.priority - b.priority);
@@ -73,5 +75,43 @@ export function createSlots(emitFn) {
         names() {
             return [..._registry.keys()];
         },
+
+        /**
+         * Render all components registered in a slot.
+         * Each component is called with the context object. Errors are
+         * caught so one broken contributor doesn't break the host surface.
+         * @param {string} name — slot name
+         * @param {object} context — props passed to each component
+         * @returns {Array} — array of rendered vnodes (nulls filtered)
+         */
+        renderAll(name, context = {}) {
+            return this.get(name).map(e => {
+                try {
+                    return e.component(context);
+                } catch (err) {
+                    console.error(`[sw.slots] Error rendering "${e.id}" in slot "${name}":`, err);
+                    return null;
+                }
+            }).filter(Boolean);
+        },
+
+        /**
+         * Declare a slot for discoverability. Runtime-only metadata —
+         * does not affect registration or rendering.
+         * @param {string} name — slot name
+         * @param {string} description — human-readable purpose
+         */
+        declare(name, description) {
+            if (!_declarations) _declarations = new Map();
+            _declarations.set(name, description);
+        },
+
+        /**
+         * List declared slot metadata (from declare()).
+         * @returns {Map<string, string>}
+         */
+        declarations() {
+            return _declarations ? new Map(_declarations) : new Map();
+        },
     };
 }