Return stats in callback

lib/cartodb/backends/turbo-carto-postgres-datasource.js

@@ -77,11 +77,14 @@ PostgresDatasource.prototype.getRamp = function (column, buckets, method, callba
             return callback(err);
         }
 
-        resultSet = resultSet || {};
-        var result = resultSet.rows || [];
-
+        var result = getResult(resultSet);
         var strategy = method2strategy[methodName];
-        var ramp = result[0][methodName] || [];
+        var ramp = result[methodName] || [];
+        var stats = {
+            min_val: result.min_val,
+            max_val: result.max_val,
+            avg_val: result.avg_val
+        };
         // Skip null values from ramp
         // Generated turbo-carto won't be correct, but better to keep it working than failing
         // TODO fix cartodb-postgres extension quantification functions
@@ -92,8 +95,16 @@ PostgresDatasource.prototype.getRamp = function (column, buckets, method, callba
             });
         }
 
-        return callback(null, { ramp: ramp, strategy: strategy });
+        return callback(null, { ramp: ramp, strategy: strategy, stats: stats });
     }, true); // use read-only transaction
 };
 
+function getResult(resultSet) {
+    resultSet = resultSet || {};
+    var result = resultSet.rows || [];
+    result = result[0] || {};
+
+    return result;
+}
+
 module.exports = PostgresDatasource;