Merge pull request #44 from alippo-com/fix/lateinit-of-featureDataModel

fix: late initialization error of the featureDataModel.

CHANGELOG.md

@@ -1,4 +1,7 @@
-# 2.0.1+0
+# 2.1.0+0
+- Fixes [issue](https://github.com/alippo-com/GrowthBook-SDK-Flutter/issues)
+
+## 2.0.1+0
 - Fixes [issue](https://github.com/alippo-com/GrowthBook-SDK-Flutter/issues/36) caused by analyzer.
 
 ## 2.0.0+0

README.md

@@ -28,7 +28,7 @@ GrowthBook is an open source feature flagging and experimentation platform that
 
 1. Add GrowthBook SDK as dependency in your pubspec.yaml file.
 ```yaml
-growthbook_sdk_flutter: ^1.1.0
+growthbook_sdk_flutter: ^latest-version
 ```
 
 ## Integration

example/lib/main.dart

@@ -4,7 +4,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:growthbook_sdk_flutter/growthbook_sdk_flutter.dart';
 
-void main() {
+void main() async {
   runApp(const MyApp());
 }
 
@@ -45,7 +45,7 @@ class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
   /// Initialization of controllers.
   late TabController _tabController;
   final userAttr = {"id": Platform.isIOS ? "foo" : "foo_bar"};
-  late final GrowthBookSDK gb;
+  GrowthBookSDK? gb;
   @override
   void initState() {
     super.initState();
@@ -60,12 +60,15 @@ class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
       hostURL: 'https://example.growthbook.io/',
       attributes: userAttr,
       growthBookTrackingCallBack: (exp, rst) {},
+      gbFeatures: {
+        'some-feature': GBFeature(defaultValue: true),
+      },
     ).initialize();
     setState(() {});
   }
 
   Widget _getRightWidget() {
-    if (gb.feature('random').on!) {
+    if (gb?.feature('some-feature').on! ?? false) {
       return TabBar(
         isScrollable: true,
         tabs: tabs,
@@ -103,13 +106,6 @@ class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
                       mainAxisSize: MainAxisSize.min,
                       children: [
                         Text(tabNames[i]),
-                        ElevatedButton(
-                          onPressed: () {
-                            //
-                            gb.features.forEach((key, value) {});
-                          },
-                          child: const Text('Press'),
-                        )
                       ],
                     ),
                   ),

lib/src/Evaluator/experiment_evaluator.dart

@@ -5,7 +5,7 @@ import 'package:growthbook_sdk_flutter/growthbook_sdk_flutter.dart';
 class GBExperimentEvaluator {
   /// Takes Context & Experiment & returns Experiment Result
 
-  GBExperimentResult evaluateExperiment({
+  static GBExperimentResult evaluateExperiment({
     required GBContext context,
     required GBExperiment experiment,
   }) {
@@ -14,40 +14,53 @@ class GBExperimentEvaluator {
     ///
     /// If context.enabled is false, return immediately (not in experiment, variationId 0)
     if (experiment.variations.length < 2 || !context.enabled!) {
-      return _getExperimentResult(experiment: experiment, gbContext: context);
+      return _getExperimentResult(
+        experiment: experiment,
+        gbContext: context,
+      );
     }
 
     /// If context.forcedVariations[experiment.trackingKey] is defined,
     /// return immediately (not in experiment, forced variation)
     final forcedVariation = context.forcedVariation?[experiment.key];
     if (forcedVariation != null) {
       return _getExperimentResult(
-          experiment: experiment,
-          variationIndex: forcedVariation,
-          gbContext: context);
+        experiment: experiment,
+        variationIndex: forcedVariation,
+        gbContext: context,
+      );
     }
 
     /// If experiment.action is set to false, return immediately
     /// (not in experiment, variationId 0)
     if (experiment.deactivated) {
-      return _getExperimentResult(experiment: experiment, gbContext: context);
+      return _getExperimentResult(
+        experiment: experiment,
+        gbContext: context,
+      );
     }
 
     // Get the user hash attribute and value (context.attributes[experiment.hashAttribute || "id"])
     // and if empty, return immediately (not in experiment, variationId 0)
     final attributeValue =
         context.attributes?[experiment.hashAttribute ?? Constant.idAttribute];
     if (attributeValue == null || attributeValue.toString().isEmpty) {
-      return _getExperimentResult(experiment: experiment, gbContext: context);
+      return _getExperimentResult(
+        experiment: experiment,
+        gbContext: context,
+      );
     }
 
     /// If experiment.namespace is set, check if hash value is included in the
     ///  range and if not, return immediately (not in experiment, variationId 0)
     if (experiment.namespace != null) {
-      var namespace = const GBUtils().getGBNameSpace(experiment.namespace!);
-      if (experiment.namespace != null &&
-          !const GBUtils().inNamespace(attributeValue, namespace!)) {
-        return _getExperimentResult(experiment: experiment, gbContext: context);
+      var namespace = GBUtils.getGBNameSpace(experiment.namespace!);
+      if (namespace != null &&
+          !GBUtils.inNamespace(attributeValue, namespace)) {
+        return _getExperimentResult(
+          experiment: experiment,
+          gbContext: context,
+        );
       }
     }
 
@@ -57,7 +70,10 @@ class GBExperimentEvaluator {
       final attr = context.attributes;
       if (!GBConditionEvaluator()
           .evaluateCondition(attr!, experiment.condition!)) {
-        return _getExperimentResult(experiment: experiment, gbContext: context);
+        return _getExperimentResult(
+          experiment: experiment,
+          gbContext: context,
+        );
       }
     }
 
@@ -66,15 +82,16 @@ class GBExperimentEvaluator {
     if (weights == null) {
       // Default weights to an even split between all variations
       experiment.weights =
-          const GBUtils().getEqualWeights(experiment.variations.length);
+          GBUtils.getEqualWeights(experiment.variations.length);
     }
 
+    // Default coverage 1.
     final coverage = experiment.coverage ?? 1.0;
     experiment.coverage = coverage;
 
     /// Calculate bucket ranges for the variations
     /// Convert weights/coverage to ranges
-    final List<GBBucketRange> bucketRange = const GBUtils().getBucketRanges(
+    final List<GBBucketRange> bucketRange = GBUtils.getBucketRanges(
         experiment.variations.length,
         coverage,
         experiment.weights != null
@@ -83,14 +100,14 @@ class GBExperimentEvaluator {
                 .toList()
             : []);
 
-    final hash = const GBUtils().hash(attributeValue + experiment.key);
-    late final int assigned;
-    if (hash != null) {
-      assigned = const GBUtils().chooseVariation(hash, bucketRange);
-    }
+    final hash = GBUtils.hash(attributeValue + experiment.key);
+    final assigned = const GBUtils().chooseVariation(hash, bucketRange);
     // If not assigned a variation (assigned === -1), return immediately (not in experiment, variationId 0)
     if (assigned == -1) {
-      return _getExperimentResult(experiment: experiment, gbContext: context);
+      return _getExperimentResult(
+        experiment: experiment,
+        gbContext: context,
+      );
     }
 
     /// If experiment.force is set, return immediately (not in experiment,
@@ -100,14 +117,16 @@ class GBExperimentEvaluator {
       return _getExperimentResult(
         experiment: experiment,
         variationIndex: forceExp,
-        inExperiment: false,
         gbContext: context,
       );
     }
 
     // If context.qaMode is true, return immediately (not in experiment, variationId 0)
     if (context.qaMode ?? false) {
-      return _getExperimentResult(experiment: experiment, gbContext: context);
+      return _getExperimentResult(
+        experiment: experiment,
+        gbContext: context,
+      );
     }
 
     final result = _getExperimentResult(
@@ -116,17 +135,19 @@ class GBExperimentEvaluator {
       inExperiment: true,
       gbContext: context,
     );
-    context.trackingCallBack!(experiment, result);
+
+    context.trackingCallBack?.call(experiment, result);
 
     return result;
   }
 
   ///  This is a helper method to create an ExperimentResult object.
-  GBExperimentResult _getExperimentResult(
-      {required GBContext gbContext,
-      required GBExperiment experiment,
-      int variationIndex = 0,
-      bool inExperiment = false}) {
+  static GBExperimentResult _getExperimentResult({
+    required GBContext gbContext,
+    required GBExperiment experiment,
+    int variationIndex = 0,
+    bool inExperiment = false,
+  }) {
     var targetVariationIndex = variationIndex;
 
     // Check whether variationIndex lies within bounds of variations size
@@ -146,14 +167,14 @@ class GBExperimentEvaluator {
     // Hash Attribute - used for Experiment Calculations
     final hashAttribute = experiment.hashAttribute ?? Constant.idAttribute;
     // Hash Value against hash attribute
-    final hashValue = gbContext.attributes?[hashAttribute];
+    final hashValue = gbContext.attributes?[hashAttribute]?.toString() ?? '';
 
     return GBExperimentResult(
       inExperiment: inExperiment,
       variationID: targetVariationIndex,
       value: targetValue,
       hasAttributes: hashAttribute,
-      hashValue: hashValue as String?,
+      hashValue: hashValue,
     );
   }
 }

lib/src/Evaluator/feature_evaluator.dart

@@ -5,7 +5,7 @@ import 'package:growthbook_sdk_flutter/growthbook_sdk_flutter.dart';
 /// Returns Calculated Feature Result against that key
 
 class GBFeatureEvaluator {
-  GBFeatureResult evaluateFeature(GBContext context, String featureKey) {
+  static GBFeatureResult evaluateFeature(GBContext context, String featureKey) {
     /// If we are not able to find feature on the basis of the passed featureKey
     /// then we are going to return unKnownFeature.
     final targetFeature = context.features[featureKey];
@@ -44,10 +44,10 @@ class GBFeatureEvaluator {
               continue;
             } else {
               // Compute a hash using the Fowler–Noll–Vo algorithm (specifically fnv32-1a)
-              final hashFNV = GBUtils().hash(attributeValue + featureKey);
+              final hashFNV = GBUtils.hash(attributeValue + featureKey);
               // If the hash is greater than rule.coverage, skip the rule
 
-              if (hashFNV != null && hashFNV > rule.coverage!) {
+              if (hashFNV > rule.coverage!) {
                 continue;
               }
             }
@@ -58,16 +58,20 @@ class GBFeatureEvaluator {
           );
         } else {
           final exp = GBExperiment(
-              key: rule.key ?? featureKey,
-              variations: rule.variations ?? [],
-              coverage: rule.coverage,
-              weights: rule.weights,
-              hashAttribute: rule.hashAttribute,
-              namespace: rule.namespace,
-              force: rule.force);
+            key: rule.key ?? featureKey,
+            variations: rule.variations ?? [],
+            coverage: rule.coverage,
+            weights: rule.weights,
+            hashAttribute: rule.hashAttribute,
+            namespace: rule.namespace,
+            force: rule.force,
+          );
+
+          final result = GBExperimentEvaluator.evaluateExperiment(
+            context: context,
+            experiment: exp,
+          );
 
-          final result = GBExperimentEvaluator()
-              .evaluateExperiment(context: context, experiment: exp);
           if (result.inExperiment ?? false) {
             return _prepareResult(
               value: result.value,
@@ -84,13 +88,14 @@ class GBFeatureEvaluator {
     }
     // Return (value = defaultValue or null, source = defaultValue)
     return _prepareResult(
-        value: targetFeature.defaultValue,
-        source: GBFeatureSource.defaultValue);
+      value: targetFeature.defaultValue,
+      source: GBFeatureSource.defaultValue,
+    );
   }
 
   /// This is a helper method to create a FeatureResult object.
   /// Besides the passed-in arguments, there are two derived values - on and off, which are just the value cast to booleans.
-  GBFeatureResult _prepareResult(
+  static GBFeatureResult _prepareResult(
       {required dynamic value,
       required GBFeatureSource source,
       GBExperiment? experiment,

lib/src/Features/feature_data_source.dart

@@ -1,33 +1,31 @@
 import 'package:growthbook_sdk_flutter/growthbook_sdk_flutter.dart';
 
+typedef FeatureFetchSuccessCallBack = void Function(
+  FeaturedDataModel featuredDataModel,
+);
+
 abstract class FeaturesFlowDelegate {
   void featuresFetchedSuccessfully(GBFeatures gbFeatures);
+  void featuresFetchFailed(GBError? error);
 }
 
 class FeatureDataSource {
-  FeatureDataSource(
-      {required this.context, required this.client, required this.onError});
+  FeatureDataSource({
+    required this.context,
+    required this.client,
+  });
   final GBContext context;
   final BaseClient client;
-  final OnError onError;
 
-  Future<FeaturedDataModel> fetchFeatures() async {
+  Future<void> fetchFeatures(
+      FeatureFetchSuccessCallBack onSuccess, OnError onError) async {
     final api = context.hostURL! + Constant.featurePath + context.apiKey!;
-    await client.consumeGetRequest(api, onSuccess, onError);
-    setUpModel();
-    return model;
-  }
-
-  late FeaturedDataModel model;
-  late Map<String, dynamic> data;
-
-  /// Assign response to local variable [data]
-  void onSuccess(response) {
-    data = response;
-  }
-
-  /// Initialize [model] from the [data]
-  void setUpModel() {
-    model = FeaturedDataModel.fromJson(data);
+    await client.consumeGetRequest(
+      api,
+      (response) => onSuccess(
+        FeaturedDataModel.fromJson(response),
+      ),
+      onError,
+    );
   }
 }