diff --git a/src/ConfigMergeCommand.js b/src/ConfigMergeCommand.js
index e662cbf..407fee8 100644
--- a/src/ConfigMergeCommand.js
+++ b/src/ConfigMergeCommand.js
@@ -1,5 +1,6 @@
 import {
-    mergeWith
+    mergeWith,
+    isObject
 } from 'lodash';
 import ConfigCommand from './ConfigCommand';
 
@@ -15,8 +16,12 @@ class ConfigMergeCommand extends ConfigCommand {
         const value = this.optionsResolver.resolve(config, options);
 
         mergeWith(config, value, (x, y) => { // eslint-disable-line consistent-return
-            if (Array.isArray(x)) {
-                return x.concat(y);
+            if (Array.isArray(x) && Array.isArray(y)) {
+                return [...x, ...y];
+            } else if (Array.isArray(x) && isObject(y)) {
+                return [...x, y];
+            } else if (isObject(x) && Array.isArray(y)) {
+                return [x, ...y];
             }
         });
     }
diff --git a/test/ConfigMergeCommand.spec.js b/test/ConfigMergeCommand.spec.js
index 52ffff4..d846c3d 100644
--- a/test/ConfigMergeCommand.spec.js
+++ b/test/ConfigMergeCommand.spec.js
@@ -18,35 +18,103 @@ describe('ConfigMergeCommand', () => {
     });
 
     describe('#execute()', () => {
-        it('should execute successfully', () => {
-            command.execute(config, {
-                foo: {
-                    bar: 'bar1'
-                },
-                bar: ['bar1']
-            });
-            command.execute(config, {
-                foo: {
-                    bar: 'bar2'
-                },
-                bar: ['bar2']
-            });
+        it('should execute successfully for `Function~>(Config|Undefined)`', () => {
             command.execute(config, x => {
                 expect(x).toBe(config);
 
                 return {
-                    foo: {
-                        bar: 'bar3'
+                    obj: {
+                        obj1: 'fn1'
                     }
                 };
             });
             command.execute(config, () => {});
+            command.execute(config, () => {
+                return {
+                    obj: {
+                        obj1: 'fn2'
+                    }
+                };
+            });
+
+            expect(config.toObject()).toEqual({
+                obj: {
+                    obj1: 'fn2'
+                }
+            });
+        });
+
+        it('should execute successfully for `Object~>Object`', () => {
+            command.execute(config, {
+                obj: {
+                    obj1: 'obj1'
+                }
+            });
+            command.execute(config, {
+                obj: {
+                    obj1: 'obj2'
+                }
+            });
+
+            expect(config.toObject()).toEqual({
+                obj: {
+                    obj1: 'obj2'
+                }
+            });
+        });
+
+        it('should execute successfully for `Object[]~>Object[]`', () => {
+            command.execute(config, {
+                arr: ['arr1']
+            });
+            command.execute(config, {
+                arr: ['arr2']
+            });
+
+            expect(config.toObject()).toEqual({
+                arr: ['arr1', 'arr2']
+            });
+        });
+
+        it('should execute successfully for `Object[]~>Object`', () => {
+            command.execute(config, {
+                arr: [{
+                    arr1: 'arr1'
+                }]
+            });
+            command.execute(config, {
+                arr: {
+                    arr2: 'arr2'
+                }
+            });
+
+            expect(config.toObject()).toEqual({
+                arr: [{
+                    arr1: 'arr1'
+                }, {
+                    arr2: 'arr2'
+                }]
+            });
+        });
+
+        it('should execute successfully for `Object~>Object[]`', () => {
+            command.execute(config, {
+                obj: {
+                    obj1: 'obj1'
+                }
+            });
+            command.execute(config, {
+                obj: [{
+                    obj2: 'obj2'
+                }]
+            });
 
             expect(config.toObject()).toEqual({
-                foo: {
-                    bar: 'bar3'
-                },
-                bar: ['bar1', 'bar2']
+                obj: [{
+                    obj1: 'obj1'
+                }, {
+                    obj2: 'obj2'
+                }]
             });
         });
     });