first draft but not working yet

controllers/store.js

@@ -0,0 +1,23 @@
+export class StoreController {
+    constructor(host, store, selector) {
+      this.host = host
+      this.store = store
+      this.selector = selector
+      host.addController(this)
+    }
+  
+    hostConnected() {
+      this._unsub = this.store.subscribe(
+        (state) => {
+          const next = this.selector(state)
+          if (next !== this.value) {
+            this.value = next
+            this.host.requestUpdate()
+          }
+        }
+      )
+      this.value = this.selector(this.store.getState())
+    }
+  
+    hostDisconnected() { this._unsub?.() }
+  }