diff --git a/lib/core.js b/lib/core.js
index e54548399..693f7bd49 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -944,19 +944,63 @@
                     for(var key in r.data) {
                         var v = r.data[key];
 
+                        // TODO: work with arrays?
                         if (v !== '' && v !== null && ((typeof v === 'string' && !/^\s+$/.test(v)) || typeof v === 'number' || typeof v === 'object')) {
 
                             // Check meta plugins order.
                             allResults.vars._sources = allResults.vars._sources || {};
 
-                            var prevOrder = null, nextOrder = null, pluginId = allResults.vars._sources[key];
+                            var prevOrder = null, nextOrder = null, prevPluginId = allResults.vars._sources[key];
 
-                            if (pluginId && plugins[pluginId] && plugins[r.method.pluginId]) {
-                                prevOrder = plugins[pluginId].order;
+                            if (prevPluginId && plugins[prevPluginId] && plugins[r.method.pluginId]) {
+                                prevOrder = plugins[prevPluginId].order;
                                 nextOrder = plugins[r.method.pluginId].order;
                             }
 
-                            if (!prevOrder || !nextOrder || prevOrder < nextOrder) {
+                            var oldValue = allResults.vars[key];
+
+                            var newValueOverrides = !prevOrder || !nextOrder || prevOrder < nextOrder;
+
+                            if (typeof v === 'object' && typeof oldValue === 'object' || Array.isArray(oldValue)) {
+
+                                var isArrayMode = Array.isArray(v) || Array.isArray(oldValue);
+
+                                if (isArrayMode) {
+                                    // Join arrays mode.
+                                    if (!Array.isArray(v)) {
+                                        v = [v];
+                                    }
+                                    if (!Array.isArray(oldValue)) {
+                                        oldValue = [oldValue];
+                                    }
+
+                                    // Keep order by priority.
+                                    if (newValueOverrides) {
+                                        allResults.vars[key] = oldValue.concat(v);
+                                    } else {
+                                        allResults.vars[key] = v.concat(oldValue);
+                                    }
+
+                                } else {
+                                    // Merge object mode.
+                                    if (newValueOverrides) {
+                                        // Extend existing object.
+                                        Object.assign(oldValue, v);
+                                    } else {
+                                        // Extend with old values on top.
+                                        allResults.vars[key] = Object.assign(v, oldValue);
+                                    }
+                                }
+
+                                if (!Array.isArray(allResults.vars._sources[key])) {
+                                    // Convert sources list to array.
+                                    allResults.vars._sources[key] = [allResults.vars._sources[key]];
+                                }
+                                allResults.vars._sources[key].push(r.method.pluginId);
+                                    
+                            } else if (newValueOverrides) {
+
+                                // Assign new non object value.
                                 allResults.vars[key] = v;
                                 allResults.vars._sources[key] = r.method.pluginId;
                             }
diff --git a/lib/loader/pluginLoader.js b/lib/loader/pluginLoader.js
index 55bf9473d..e9b7b807c 100644
--- a/lib/loader/pluginLoader.js
+++ b/lib/loader/pluginLoader.js
@@ -269,6 +269,23 @@
                 return;
             }
 
+            // Log custom plugin attributes.
+            // for(var plugin_key in plugin) {
+            //     if (PLUGINS_FIELDS.indexOf(plugin_key) === -1 
+            //         && PLUGIN_METHODS.indexOf(plugin_key) === -1
+            //         && ['provides', 
+            //             'listed', 
+            //             'tests', 
+            //             're', 
+            //             'notPlugin', 
+            //             'highestPriority', 
+            //             'lowestPriority', 
+            //             'startIteration', 
+            //             'finishIteration'].indexOf(plugin_key) === -1) {
+            //         console.log('--- unknown plugin attr', getFileName(bits[bits.length - 1]), plugin_key)
+            //     }
+            // }
+
             // Check post plugin.
             // TODO: only prapereLink method abailable.
             // TODO: exclude prapereLink method from other plugins.