diff --git a/lib/services/options.service.ts b/lib/services/options.service.ts
index a42d342f..66ead611 100644
--- a/lib/services/options.service.ts
+++ b/lib/services/options.service.ts
@@ -1,6 +1,6 @@
 'use strict';
 import { Injectable } from '@angular/core';
-import { isFunction, isString } from '@angular/core/src/facade/lang';
+import { isFunction, isString } from '../utils/helpers';
 import { BrowserDomAdapter as DOM } from '../utils/browser-adapter';
 
 const defaults = {
diff --git a/lib/utils/JsonFormatterPipe.ts b/lib/utils/JsonFormatterPipe.ts
index 4c3006af..3be316e6 100644
--- a/lib/utils/JsonFormatterPipe.ts
+++ b/lib/utils/JsonFormatterPipe.ts
@@ -1,6 +1,5 @@
 'use strict';
 import { Pipe, PipeTransform } from '@angular/core';
-//import { isBlank } from '@angular/core/src/facade/lang';
 import { DomSanitizer } from '@angular/platform-browser';
 
 function isBlank(obj) {
diff --git a/lib/utils/helpers.ts b/lib/utils/helpers.ts
index c2d169e5..991526bf 100644
--- a/lib/utils/helpers.ts
+++ b/lib/utils/helpers.ts
@@ -21,6 +21,22 @@ interface HeadersHandler {
   close: Function;
 }
 
+export function stringify(obj:any) {
+  return JSON.stringify(obj);
+}
+
+export function isString(str:any) {
+  return typeof str === 'string';
+}
+
+export function isFunction(func: any) {
+  return typeof func === 'function';
+}
+
+export function isBlank(obj: any): boolean {
+  return obj == null;
+}
+
 export function renderMd(rawText:string, headersHandler?:HeadersHandler) {
   let _origRule;
   if (headersHandler) {
diff --git a/lib/utils/pipes.ts b/lib/utils/pipes.ts
index a318fce4..a28a4728 100644
--- a/lib/utils/pipes.ts
+++ b/lib/utils/pipes.ts
@@ -2,7 +2,7 @@
 
 import { Pipe, PipeTransform } from '@angular/core';
 import { DomSanitizer } from '@angular/platform-browser';
-import { isString, stringify, isBlank } from '@angular/core/src/facade/lang';
+import { isString, stringify, isBlank } from './helpers';
 import JsonPointer from './JsonPointer';
 import { renderMd } from './helpers';
 import { JsonFormatter } from './JsonFormatterPipe';