app/model: Hub: Fix reverted changes

app/model/Hub.js

@@ -55,25 +55,41 @@ class Hub {
         indexLambda(id, locations)
       })
 
-      let userId = await promise
-
-      // Remove indexed locations.
-      unindexLambda(id, locations)
-
-      return userId
+      try {
+        return await promise
+      } finally {
+        // Remove indexed locations.
+        unindexLambda(id, locations)
+
+        delete this.drivers[id]
+      }
     }
   }
 
   filter (location) {
-    return this.locations[location]
+    return [...this.locations[location] || []]
   }
 
   pick (id, userId) {
-    this.drivers[id].resolve(userId)
+    let handle = this.drivers[id]
+
+    if (handle) {
+      handle.resolve(userId)
+      return true
+    }
+
+    return false
   }
 
   reject (id, reason) {
-    this.drivers[id].reject(reason)
+    let handle = this.drivers[id]
+
+    if (handle) {
+      handle.reject(reason)
+      return true
+    }
+
+    return false
   }
 }