diff --git a/__tests__/helpers.spec.js b/__tests__/helpers.spec.js
index 745829c..6d8f086 100644
--- a/__tests__/helpers.spec.js
+++ b/__tests__/helpers.spec.js
@@ -24,6 +24,23 @@ describe('merge', () => {
       }
     })
   })
+
+  it ('should merge objects containing non-objects', () => {
+    const a = { c: [ 1, 2, 3 ], d: Promise.resolve({ a: 1 }) }
+    const b = { c: [ 4, 5 ], d: { b: 1 } }
+    const c = helpers.merge(a, b)
+
+    expect(c).toEqual({
+      c: [
+        4,
+        5,
+        3
+      ],
+      d: {
+        b: 1
+      }
+    })
+  })
 })
 
 describe('getMethod', () => {
diff --git a/src/helpers.js b/src/helpers.js
index 0a05fcf..fd9ef65 100644
--- a/src/helpers.js
+++ b/src/helpers.js
@@ -30,7 +30,9 @@ export function getBasePath (base, path) {
 
 export function merge (obj, src) {
   Object.keys(src).forEach(function (key) {
-    if (obj[key] && typeof obj[key] === 'object') {
+    const type = obj[key] && Object.prototype.toString.call(obj[key])
+
+    if (type === '[object Object]' || type === '[object Array]') {
       merge(obj[key], src[key])
       return
     }