Allow iterating through datastores like a Map

Support the for (const [k, v] of datastore) syntax which is commonly
used with maps by adding a Symbol.iterator function returning the
appropriate iterator.

packages/lib/src/datastore.ts

@@ -184,6 +184,11 @@ export abstract class Datastore<
 		return this.data.get(key);
 	}
 
+	// Allow iterating through the datastore like a Map.
+	[Symbol.iterator](): IterableIterator<[K, Readonly<V>]> {
+		return this.data.entries();
+	}
+
 	// Returns all values in the datastore
 	values() {
 		return this.data.values() as IterableIterator<Readonly<V>>;