Fix: variants-batch (#4222)

## About the changes
Fix un-awaited promise on batch variant update - reduce function allowed
TS to skip Promise type.

---------

Co-authored-by: Gastón Fournier <gaston@getunleash.io>

src/lib/services/feature-toggle-service.ts

@@ -1837,17 +1837,14 @@ class FeatureToggleService {
     ): Promise<IVariant[]> {
         await variantsArraySchema.validateAsync(newVariants);
         const fixedVariants = this.fixVariantWeights(newVariants);
-        const oldVariants: { [env: string]: IVariant[] } = environments.reduce(
+        const oldVariants: { [env: string]: IVariant[] } = {};
-            async (result, environment) => {
+        for (const env of environments) {
-                result[environment] = await this.featureEnvironmentStore.get({
+            const featureEnv = await this.featureEnvironmentStore.get({
-                    featureName,
+                featureName,
-                    environment,
+                environment: env,
-                });
+            });
-                return result;
+            oldVariants[env] = featureEnv.variants || [];
-            },
+        }
-            {},
-        );
-
         await this.eventStore.batchStore(
             environments.map(
                 (environment) =>

src/test/e2e/api/admin/project/variants.e2e.test.ts

@@ -305,6 +305,25 @@ test('Can push variants to multiple environments', async () => {
         });
 });
 
+test("Returns proper error if project and/or feature toggle doesn't exist", async () => {
+    await app.request
+        .put(
+            `/api/admin/projects/nonexistent/features/undefined/variants-batch`,
+        )
+        .send({
+            variants: [
+                {
+                    name: 'new-variant-1',
+                    stickiness: 'default',
+                    weight: 500,
+                    weightType: WeightType.VARIABLE,
+                },
+            ],
+            environments: ['development', 'production'],
+        })
+        .expect(404);
+});
+
 test('Can add variant for a feature', async () => {
     const featureName = 'feature-variants-patch-add';
     const variantName = 'fancy-variant-patch';