fix: loading database crashes if collections are missing

packages/@cdklabs/tskb/src/database.ts

@@ -207,7 +207,11 @@ export class Database<ES extends object, RS extends object> {
       }
       if (!!proto && typeof proto === 'object' && !!x && typeof x === 'object') {
         for (const [k, v] of Object.entries(proto)) {
-          hydrate(v, (x as any)[k]);
+          const dehydratedData = (x as any)[k];
+          if (dehydratedData !== undefined) {
+            // May be missing if this is from a database created from an old version of the schema
+            hydrate(v, dehydratedData);
+          }
         }
       }
     }

packages/@cdklabs/tskb/test/entity.test.ts

@@ -69,6 +69,13 @@ describe.each([false, true])('database is filled with one item (saveAndLoad: %p)
   });
 });
 
+test('can dehydrate from a data where the collection is missing without crashing', () => {
+  db.load({
+    idCtr: 1,
+    schema: {},
+  });
+});
+
 describe.each([false, true])('database is filled with multiple items (saveAndLoad: %p)', (saveAndLoad) => {
   beforeEach(() => {
     db.allocate('thing', {

packages/@cdklabs/tskb/test/relationship.test.ts

@@ -29,6 +29,13 @@ beforeEach(() => {
   db = emptyDatabase();
 });
 
+test('can dehydrate from a data where the collections are missing without crashing', () => {
+  db.load({
+    idCtr: 1,
+    schema: {},
+  });
+});
+
 describe.each([false, true])('database with some entities (saveAndLoad: %p)', (saveAndLoad) => {
   beforeEach(() => {
     const a = db.allocate('thing', {