Promises rejected properly when loading wrong content

http/http.ts

@@ -6,14 +6,28 @@ global.moduleMerge(httpRequest, exports);
 export function getString(arg: any): Promise<string> {
     return new Promise<string>((resolve, reject) => {
         httpRequest.request(typeof arg === "string" ? { url: arg, method: "GET" } : arg)
-            .then(r => resolve(r.content.toString()), e => reject(e));
+            .then(r => {
+            try {
+                var str = r.content.toString();
+                resolve(str);
+            } catch (e) {
+                reject(e);
+            }
+        }, e => reject(e));
     });
 }
 
 export function getJSON<T>(arg: any): Promise<T> {
     return new Promise<T>((resolve, reject) => {
         httpRequest.request(typeof arg === "string" ? { url: arg, method: "GET" } : arg)
-            .then(r => resolve(r.content.toJSON()), e => reject(e));
+            .then(r => {
+            try {
+                var json = r.content.toJSON();
+                resolve(json);
+            } catch (e) {
+                reject(e);
+            }
+        }, e => reject(e));
     });
 }
 
@@ -21,7 +35,7 @@ export function getImage(arg: any): Promise<image.ImageSource> {
     return new Promise<image.ImageSource>((resolve, reject) => {
         httpRequest.request(typeof arg === "string" ? { url: arg, method: "GET" } : arg)
             .then(r => {
-            r.content.toImage().then(source => resolve(source));
+            r.content.toImage().then(source => resolve(source), e => reject(e));
         }, e => reject(e));
     });
 }