fix(flagd): improve targeting key check in fractional operator (open-feature#1048)

Signed-off-by: Michael Beemer <beeme1mr@users.noreply.github.com>

Author: beeme1mr

libs/shared/flagd-core/src/lib/targeting/fractional.ts

@@ -29,12 +29,12 @@ export function fractionalFactory(logger: Logger) {
       bucketBy = args[0];
       buckets = args.slice(1, args.length);
     } else {
-      bucketBy = `${flagdProperties[flagKeyPropertyKey]}${context[targetingPropertyKey]}`;
-      if (!bucketBy) {
+      const targetingKey = context[targetingPropertyKey];
+      if (!targetingKey) {
         logger.debug('Missing targetingKey property, cannot perform fractional targeting');
         return null;
       }
-
+      bucketBy = `${flagdProperties[flagKeyPropertyKey]}${targetingKey}`;
       buckets = args;
     }
 

libs/shared/flagd-core/src/lib/targeting/targeting.spec.ts

@@ -187,6 +187,17 @@ describe('fractional operator', () => {
 
     expect(targeting.applyTargeting('flagA', input, { targetingKey: 'bucketKeyB' })).toBe('blue');
   });
+
+  it('should return null if targeting key is missing', () => {
+    const input = {
+      fractional: [
+        ['red', 1],
+        ['blue', 1],
+      ],
+    };
+
+    expect(targeting.applyTargeting('flagA', input, {})).toBe(null);
+  });
 });
 
 describe('fractional operator should validate', () => {