Space preferences for whether or not you see DMs in a Space (#7250)

src/utils/sets.ts

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { arrayDiff, Diff } from "./arrays";
+
 /**
  * Determines if two sets are different through a shallow comparison.
  * @param a The first set. Must be defined.
@@ -32,3 +34,13 @@ export function setHasDiff<T>(a: Set<T>, b: Set<T>): boolean {
         return true; // different lengths means they are naturally diverged
     }
 }
+
+/**
+ * Determines the values added and removed between two sets.
+ * @param a The first set. Must be defined.
+ * @param b The second set. Must be defined.
+ * @returns The difference between the values in each set.
+ */
+export function setDiff<T>(a: Set<T>, b: Set<T>): Diff<T> {
+    return arrayDiff(Array.from(a), Array.from(b));
+}