Merge pull request #11 from Microsoft/download-error-checking

Add an error check to the update download function

Author: Will Anderson

package-mixins.js

@@ -3,6 +3,10 @@ var extend = require("extend");
 module.exports = (NativeCodePush) => {
   var remote = {
     download: function download() {
+      if (!this.downloadUrl) {
+        return Promise.reject(new Error("Cannot download an update without a download url"));
+      }
+
       // Use the downloaded package info. Native code will save the package info
       // so that the client knows what the current package version is.
       return NativeCodePush.downloadUpdate(this)