inspect: correctly handle custom objects without class name (#2075)

Author: IvanGoncharov

src/jsutils/__tests__/inspect-test.js

@@ -177,5 +177,10 @@ describe('inspect', () => {
 
     (Foo.prototype: any)[Symbol.toStringTag] = 'Bar';
     expect(inspect([[new Foo()]])).to.equal('[[[Bar]]]');
+
+    const objectWithoutClassName = new (function() {
+      this.foo = 1;
+    })();
+    expect(inspect([[objectWithoutClassName]])).to.equal('[[[Object]]]');
   });
 });

src/jsutils/inspect.js

@@ -117,7 +117,7 @@ function getObjectTag(object) {
 
   if (tag === 'Object' && typeof object.constructor === 'function') {
     const name = object.constructor.name;
-    if (typeof name === 'string') {
+    if (typeof name === 'string' && name !== '') {
       return name;
     }
   }