wip

js/desktop/src/hooks/use-object-url.ts

@@ -0,0 +1,28 @@
+import { useEffect, useState } from "react";
+
+/**
+ * Creates an object URL for a Blob/File and revokes it when the source changes
+ * or the component unmounts. Returns null when given null.
+ *
+ * `createObjectURL` is an imperative side effect that must run inside an effect,
+ * so publishing the resulting URL to state here is genuine external-resource
+ * synchronization rather than a render cascade — hence the single, contained
+ * lint suppression below.
+ */
+export function useObjectUrl(source: Blob | null): string | null {
+  const [url, setUrl] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!source) return;
+    const objectUrl = URL.createObjectURL(source);
+    // Intended external-resource publish (see hook doc), not a render cascade.
+    // eslint-disable-next-line react-hooks/set-state-in-effect
+    setUrl(objectUrl);
+    return () => {
+      URL.revokeObjectURL(objectUrl);
+      setUrl(null); // in cleanup, not the effect body — so no suppression needed
+    };
+  }, [source]);
+
+  return source ? url : null;
+}