test: add a console warning when persistence is set up but without a …

…name

src/sync/syncObservable.ts

@@ -913,6 +913,18 @@ async function loadLocal<T>(
                 ].filter(Boolean),
             ) as unknown as Promise<void>;
     } else {
+        // Console.warn if no persist name is provided. It's ok if name is undefined as that can be the user manually disabling it,
+        // but if not provided at all it's likely user error.
+        if (
+            (process.env.NODE_ENV === 'development' || process.env.NODE_ENV === 'test') &&
+            persist &&
+            persist.plugin &&
+            !Object.hasOwn(persist, 'name')
+        ) {
+            console.warn(
+                '[legend-state] Trying to syncObservable without `name` defined. Please include a `name` property in the `persist` configuration.',
+            );
+        }
         nodeValue.resetPersistence = () => prevResetPersistence?.();
     }
     // TODOV3 Remove

tests/computed-persist.test.ts

@@ -83,6 +83,9 @@ describe('caching with new computed', () => {
         const nodes = observable(
             mySynced({
                 initial: [],
+                persist: {
+                    name: getPersistName(),
+                },
             }),
         );
 

tests/persist-indexeddb.test.ts

@@ -6,7 +6,7 @@ import { configureSynced } from '../src/sync/configureSynced';
 import { mapSyncPlugins, syncObservable } from '../src/sync/syncObservable';
 import type { ObservablePersistPlugin, ObservablePersistPluginOptions } from '../src/sync/syncTypes';
 import { when } from '../src/when';
-import { promiseTimeout } from './testglobals';
+import { expectLog, promiseTimeout } from './testglobals';
 
 const TableNameBase = 'jestlocal';
 const tableNames = Array.from({ length: 100 }, (_, i) => TableNameBase + i);
@@ -371,4 +371,19 @@ describe('Persist IDB', () => {
 
         await expectIDB(persistName, []);
     });
+    test('Persist without a name errors', async () => {
+        const obs = observable<Record<string, any>>({});
+
+        expectLog(
+            () => {
+                syncObservable(obs, {
+                    persist: {
+                        plugin: myIndexedDBPlugin,
+                    },
+                });
+            },
+            '[legend-state] Trying to syncObservable without `name` defined. Please include a `name` property in the `persist` configuration.',
+            'warn',
+        );
+    });
 });

tests/testglobals.ts

@@ -83,3 +83,10 @@ export function supressActWarning(fn: () => void) {
 
     console.error = originalError;
 }
+
+export function expectLog(fn: () => any, msg: string, logType: 'log' | 'warn' | 'error') {
+    jest.spyOn(console, logType).mockImplementation(() => {});
+    fn();
+    expect(console[logType]).toHaveBeenCalledWith(msg);
+    (console[logType] as jest.Mock).mockRestore();
+}