diff --git a/lib/components/JsonSchema/json-schema.html b/lib/components/JsonSchema/json-schema.html
index da41e5f4..c60b7a28 100644
--- a/lib/components/JsonSchema/json-schema.html
+++ b/lib/components/JsonSchema/json-schema.html
@@ -68,7 +68,7 @@
           </td>
           <td class="param-info">
             <div>
-              <span class="param-type {{prop.type}}" [ngClass]="{'with-hint': prop._displayTypeHint, 'tuple': prop._isTuple}"
+              <span class="param-type {{prop.type}}" [ngClass]="{'with-hint': prop._displayTypeHint, 'tuple': prop._isTuple, 'array': prop._isArray}"
               title="{{prop._displayTypeHint}}"> {{prop._displayType}} {{prop._displayFormat}}
               <span class="param-range" *ngIf="prop._range"> {{prop._range}} </span>
               </span>
diff --git a/lib/services/schema-helper.service.spec.ts b/lib/services/schema-helper.service.spec.ts
index 041bfe59..46c43a49 100644
--- a/lib/services/schema-helper.service.spec.ts
+++ b/lib/services/schema-helper.service.spec.ts
@@ -17,4 +17,19 @@ describe('Spec Helper', () => {
       (<jasmine.Spy>console.warn).and.callThrough();
     });
   });
+
+  describe('preprocessProperties', () => {
+    it('should not throw when type array and items are not defined', () => {
+      let schema = {
+        type: 'object',
+        properties: {
+          prop1: {
+            type: 'array'
+          }
+        }
+      };
+
+      (() => SchemaHelper.preprocessProperties(schema, '#/', {})).should.not.throw();
+    });
+  });
 });
diff --git a/lib/services/schema-helper.service.ts b/lib/services/schema-helper.service.ts
index 3fc16333..613b85f3 100644
--- a/lib/services/schema-helper.service.ts
+++ b/lib/services/schema-helper.service.ts
@@ -5,7 +5,7 @@ import { WarningsService } from './warnings.service';
 import * as slugify from 'slugify';
 
 interface PropertyPreprocessOptions {
-  childFor: string;
+  childFor?: string;
   skipReadOnly?: boolean;
   discriminator?: string;
 }
@@ -54,6 +54,7 @@ const injectors = {
       return propertySchema.type === 'array' && !Array.isArray(propertySchema.items);
     },
     inject: (injectTo, propertySchema = injectTo, propPointer) => {
+      if (!propertySchema.items) propertySchema.items = {};
       if (!(SchemaHelper.detectType(propertySchema.items) === 'object')) {
         injectTo._isArray = true;
         injectTo._pointer = propertySchema.items._pointer
@@ -207,7 +208,11 @@ export class SchemaHelper {
   static preprocessProperties(schema:any, pointer:string, opts: PropertyPreprocessOptions) {
     let requiredMap = {};
     if (schema.required) {
-      schema.required.forEach(prop => requiredMap[prop] = true);
+      if (Array.isArray(schema.required)) {
+        schema.required.forEach(prop => requiredMap[prop] = true);
+      } else {
+        WarningsService.warn(`required must be an array: "${typeof schema.required}" found at ${pointer}`);
+      }
     }
 
     let props = schema.properties && Object.keys(schema.properties).map(propName => {
diff --git a/lib/services/schema-normalizer.service.ts b/lib/services/schema-normalizer.service.ts
index 61cd728b..433d03a8 100644
--- a/lib/services/schema-normalizer.service.ts
+++ b/lib/services/schema-normalizer.service.ts
@@ -29,7 +29,7 @@ export class SchemaNormalizer {
 
     if (opts.childFor) this._dereferencer.visit(opts.childFor);
     if (schema['x-redoc-normalized']) return schema;
-      let res = SchemaWalker.walk(schema, ptr, (subSchema, ptr) => {
+    let res = SchemaWalker.walk(schema, ptr, (subSchema, ptr) => {
       let resolved = this._dereferencer.dereference(subSchema, ptr);
       if (resolved.allOf) {
         resolved._pointer = resolved._pointer || ptr;