Update object check to include instance

addon/utils/is-object.js

@@ -0,0 +1,7 @@
+import Ember from 'ember';
+
+const { typeOf } = Ember;
+
+export default function isObject(val) {
+  return typeOf(val) === 'object' || typeOf(val) === 'instance';
+}

addon/utils/is-promise.js

@@ -1,4 +1,5 @@
 import Ember from 'ember';
+import isObject from './is-object';
 
 const { typeOf } = Ember;
 
@@ -9,5 +10,5 @@ function isPromiseLike(obj = {}) {
 }
 
 export default function isPromise(obj) {
-  return typeOf(obj) === 'object' && isPromiseLike(obj);
+  return isObject(obj) && isPromiseLike(obj);
 }

tests/unit/utils/is-object-test.js

@@ -0,0 +1,34 @@
+import Ember from 'ember';
+import isObject from 'ember-composable-helpers/utils/is-object';
+import { module, test } from 'qunit';
+
+const { Object: EmberObject, ObjectProxy } = Ember;
+
+module('Unit | Utility | is object');
+
+let testData = [
+  {
+    label: 'POJOs',
+    value: { foo: 'bar' },
+    expected: true
+  },
+  {
+    label: 'EmberObjects',
+    value: EmberObject.create({ foo: 'bar' }),
+    expected: true
+  },
+  {
+    label: 'ObjectProxies',
+    value: ObjectProxy.create({
+      content: EmberObject.create({ foo: 'bar' })
+    }),
+    expected: true
+  }
+];
+
+testData.forEach(({ label, value, expected }) => {
+  test(`it works with ${label}`, function(assert) {
+    let result = isObject(value);
+    assert.equal(result, expected, `should be ${expected}`);
+  });
+});