fix(store): Memory-based storage returns null for non-existing inst…

…ance

src/store.js

@@ -280,7 +280,7 @@ function setupStorage(config, options) {
 
 function memoryStorage(config) {
   return {
-    get: config.enumerable ? () => {} : () => config.create({}),
+    get: config.enumerable ? () => null : () => config.create({}),
     set: config.enumerable
       ? (id, values) => values
       : (id, values) => (values === null ? { id } : values),
@@ -1042,7 +1042,10 @@ function get(Model, id) {
         (result === undefined || typeof result !== "object")
       ) {
         throw TypeError(
-          `Storage 'get' method must return a Promise, an instance, or null: ${result}`,
+          stringifyModel(
+            Model,
+            `Storage 'get' method must return a Promise, an instance, or null: ${result}`,
+          ),
         );
       }
 

test/spec/store.js

@@ -156,6 +156,15 @@ describe("store:", () => {
       expect(spy).toHaveBeenCalledTimes(1);
     });
 
+    it("returns a model in the error state for non-existing instance of memory based enumerable definition", () => {
+      Model = { id: true, value: "" };
+      const model = store.get(Model, "1");
+
+      expect(model).toBeInstanceOf(Object);
+      expect(store.error(model)).toBeInstanceOf(Error);
+      expect(store.error(model).message.includes("does not exist")).toBe(true);
+    });
+
     describe("for singleton", () => {
       beforeEach(() => {
         Model = {