1 files changed, 9 insertions, 8 deletions
diff --git a/js/vendor/es6-shim/test-sham/set-prototype-of.js b/js/vendor/es6-shim/test-sham/set-prototype-of.js
index d68f930fd..e46bb6a03 100644
--- a/js/vendor/es6-shim/test-sham/set-prototype-of.js
+++ b/js/vendor/es6-shim/test-sham/set-prototype-of.js
@@ -1,24 +1,25 @@
-describe('Object.setPrototypeOf(o, p)', function() {
+/*global expect */
+describe('Object.setPrototypeOf(o, p)', function () {
+  'use strict';
 
-  it('changes prototype to regular objects', function() {
+  it('changes prototype to regular objects', function () {
     var obj = {a: 123};
-    expect(obj instanceof Object).to.equal(true);
+    expect(obj).to.be.an.instanceOf(Object);
     // sham requires assignment to work cross browser
     obj = Object.setPrototypeOf(obj, null);
-    expect(obj instanceof Object).to.equal(false);
+    expect(obj).not.to.be.an.instanceOf(Object);
     expect(obj.a).to.equal(123);
   });
 
-  it('changes prototype to null objects', function() {
+  it('changes prototype to null objects', function () {
     var obj = Object.create(null);
     obj.a = 456;
-    expect(obj instanceof Object).to.equal(false);
+    expect(obj).not.to.be.an.instanceOf(Object);
     expect(obj.a).to.equal(456);
     // sham requires assignment to work cross browser
     obj = Object.setPrototypeOf(obj, {});
-    expect(obj instanceof Object).to.equal(true);
+    expect(obj).to.be.an.instanceOf(Object);
     expect(obj.a).to.equal(456);
   });
 
 });
-