feat(api): Feature variable APIs now return default variable value when featureEnabled property is false. (#249)

Author: mfahadahmed

packages/optimizely-sdk/lib/core/decision_service/index.tests.js

@@ -843,7 +843,7 @@ describe('lib/core/decision_service', function() {
                     ],
                     'featureEnabled': false,
                     'key': 'variation2'
-                  }
+                  },
                 },
               },
               variation: {

packages/optimizely-sdk/lib/core/project_config/index.js

@@ -496,16 +496,15 @@ module.exports = {
 
   /**
    * Get the value of the given variable for the given variation. If the given
-   * variable has no value for the given variation, return the variable's
-   * default value. Log an error message if the variation is invalid. If the
+   * variable has no value for the given variation, return null. Log an error message if the variation is invalid. If the
    * variable or variation are invalid, return null.
    * @param {Object} projectConfig
    * @param {Object} variable
    * @param {Object} variation
    * @param {Object} logger
    * @return {string|null} The value of the given variable for the given
-   * variation, or the variable default value if the given variable has no value
-   * for the given variation, or null if the variation or variable are invalid
+   * variation, or null if the given variable has no value
+   * for the given variation or if the variation or variable are invalid
    */
   getVariableValueForVariation: function(projectConfig, variable, variation, logger) {
     if (!variable || !variation) {
@@ -519,7 +518,8 @@ module.exports = {
 
     var variableUsages = projectConfig.variationVariableUsageMap[variation.id];
     var variableUsage = variableUsages[variable.id];
-    return variableUsage ? variableUsage.value : variable.defaultValue;
+
+    return variableUsage ? variableUsage.value : null;
   },
 
   /**

packages/optimizely-sdk/lib/core/project_config/index.tests.js

@@ -453,11 +453,11 @@ describe('lib/core/project_config', function() {
           assert.strictEqual(result, null);
         });
 
-        it('returns the variable default value if the variation does not have a value for this variable', function() {
+        it('returns null if the variation does not have a value for this variable', function() {
           var variation = configObj.variationIdMap['595008']; // This variation has no variable values associated with it
           var variable = configObj.featureKeyMap.test_feature_for_experiment.variableKeyMap.num_buttons;
           var result = projectConfig.getVariableValueForVariation(configObj, variable, variation, featureManagementLogger);
-          assert.strictEqual(result, '10');
+          assert.isNull(result);
         });
       });
 

packages/optimizely-sdk/lib/optimizely/index.js

@@ -632,17 +632,27 @@ Optimizely.prototype._getFeatureVariableForType = function(featureKey, variableK
     return null;
   }
 
-  var variableValue;
   var featureEnabled = false;
+  var variableValue = variable.defaultValue;
   var decision = this.decisionService.getVariationForFeature(this.configObj, featureFlag, userId, attributes);
 
   if (decision.variation !== null) {
     featureEnabled = decision.variation.featureEnabled;
-    variableValue = projectConfig.getVariableValueForVariation(this.configObj, variable, decision.variation, this.logger);
-    this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.USER_RECEIVED_VARIABLE_VALUE, MODULE_NAME, variableKey, featureFlag.key, variableValue, userId));
+    var value = projectConfig.getVariableValueForVariation(this.configObj, variable, decision.variation, this.logger);
+    if (value !== null) {
+      if (featureEnabled === true) {
+        variableValue = value;
+        this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.USER_RECEIVED_VARIABLE_VALUE, MODULE_NAME, variableKey, featureFlag.key, variableValue, userId));
+      } else {
+        this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.FEATURE_NOT_ENABLED_RETURN_DEFAULT_VARIABLE_VALUE, MODULE_NAME,
+          featureFlag.key, userId, variableKey));
+      }
+    } else {
+      this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.VARIABLE_NOT_USED_RETURN_DEFAULT_VARIABLE_VALUE, MODULE_NAME, variableKey, decision.variation.key));
+    }
   } else {
-    variableValue = variable.defaultValue;
-    this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.USER_RECEIVED_DEFAULT_VARIABLE_VALUE, MODULE_NAME, userId, variableKey, featureFlag.key));
+    this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.USER_RECEIVED_DEFAULT_VARIABLE_VALUE, MODULE_NAME, userId,
+      variableKey, featureFlag.key));
   }
 
   var experimentKey = null;