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packages/web/src/utility/memberStore.ts

@@ -0,0 +1,19 @@
+import { writable } from 'svelte/store';
+
+export default function memberStore(store, extractStore) {
+  let res;
+  let unsubscribeSub = null;
+  store.subscribe(value => {
+    const subStore = extractStore(value);
+    if (unsubscribeSub) unsubscribeSub();
+    unsubscribeSub = subStore.subscribe(subValue => {
+      if (res) {
+        console.log('subValue', subValue);
+        res.set(subValue);
+      } else {
+        res = writable(subValue);
+      }
+    });
+  });
+  return res;
+}