Fix issue about utf-8 and data.class() return undefined

Author: kefahB

demo/app/main-page.ts

@@ -42,6 +42,23 @@ export function postHttpbin() {
   postRequest('https://httpbin.org/post', {"foo": "bar", "baz": undefined, "plaz": null});
 }
 
+export function postHttpbinWithUTF8() {
+    Https.request(
+        {
+          url: 'https://httpbin.org/post',
+          method: 'POST',
+          body: {"foo": "bar", "baz": undefined, "plaz": null},
+          headers: {
+              'Content-Type': "application/json; charset=utf-8"
+          }
+        })
+        .then(response => console.log('Https.request response', response))
+        .catch(error => {
+          console.error('Https.request error', error);
+          dialogs.alert(error);
+        });
+  }  
+
 export function getHttpbin() {
   getRequest('https://httpbin.org/get');
 }

demo/app/main-page.xml

@@ -9,6 +9,7 @@
         <Button text="GET Httpbin" tap="getHttpbin" class="t-20 btn btn-primary btn-active"/>
         <Button text="GET Httpbin (large response)" tap="getHttpbinLargeResponse" class="t-20 btn btn-primary btn-active"/>
         <Button text="POST Httpbin " tap="postHttpbin" class="t-20 btn btn-primary btn-active"/>
+        <Button text="POST Httpbin UTF-8" tap="postHttpbinWithUTF8" class="t-20 btn btn-primary btn-active"/>
         <Button text="Httpbin Pinning ON" tap="enableSSLPinning" class="t-20 btn btn-primary btn-active"/>
         <Button text="Httpbin Pinning ON, expired cert" tap="enableSSLPinningExpired" class="t-20 btn btn-primary btn-active"/>
         <Button text="Httpbin Pinning OFF" tap="disableSSLPinning" class="t-20 btn btn-primary btn-active"/>

src/https.ios.ts

@@ -137,8 +137,9 @@ export function request(opts: Https.HttpsRequestOptions): Promise<Https.HttpsRes
   return new Promise((resolve, reject) => {
     try {
       const manager = AFHTTPSessionManager.alloc().initWithBaseURL(NSURL.URLWithString(opts.url));
-      const contentType = (<string>opts.headers['Content-Type']).substring(0, 16);
-      if (opts.headers && contentType === 'application/json') {
+      //const contentType = (<any>opts.headers['Content-Type']).substring(0, 16);
+      if (opts.headers && (<any>opts.headers['Content-Type']).substring(0, 16) === 'application/json') {
+          console.log(opts.headers['Content-Type'])
           manager.requestSerializer = AFJSONRequestSerializer.serializer();
           manager.responseSerializer = AFJSONResponseSerializer.serializerWithReadingOptions(NSJSONReadingOptions.AllowFragments);
       } else {