Error running app on iOS - nativescript

Question

I'm on MacOS platform now and did a full install of the tools for {N}.
I can build my app. I see it being installed on the emulator and can also see the splash screen and then crash.
** BUILD SUCCEEDED **
Project successfully built
Successfully deployed on device with identifier '7E5B1A70-9579-4510-8279-E43522B8537C'.
1 0x107ee05dc -[TNSRuntime executeModule:referredBy:]
2 0x107a0f4e2 main
Jan 16 15:09:50 macs-iMac test4[2821]: 3 0x10d72a68d start
4 0x1
[native code]: JS ERROR NSErrorWrapper: The data couldn’t be read because it isn’t in the correct format.
Jan 16 15:09:50 macs-iMac com.apple.CoreSimulator.SimDevice.7E5B1A70-9579-4510-8279-E43522B8537C.launchd_sim[2436] (UIKitApplication:org.nativescript.test4[0x3494][2821]): Service exited due to Segmentation fault: 11
Any help???
The app runs fine on Android.
I also download the groceries app on macOS and it builds and runs ok - just wanted to make sure the tools were installed properly.
I see the culprit is JS ERROR NSErrorWrapper: The data couldn’t be read because it isn’t in the correct format.
How can I find out what that could be???
{
"description": "NativeScript Application",
"license": "SEE LICENSE IN <your-license-filename>",
"readme": "NativeScript Application",
"repository": "<fill-your-repository-here>",
"nativescript": {
"id": "org.nativescript.test4",
"tns-ios": {
"version": "2.4.0"
}
},
"dependencies": {
"nativescript-calendar": "^1.2.0",
"nativescript-email": "^1.3.4",
"nativescript-imagepicker": "^2.4.1",
"nativescript-phone": "^1.2.3",
"nativescript-purchase": "^1.0.1",
"nativescript-telerik-ui": "^1.5.1",
"nativescript-theme-core": "^0.2.5",
"nativescript-themes": "^1.1.0",
"nativescript-toast": "^1.4.3",
"tns-core-modules": "^2.4.4"
},
"devDependencies": {
"babel-traverse": "6.19.0",
"babel-types": "6.19.0",
"babylon": "6.14.1",
"lazy": "1.0.11",
"nativescript-dev-android-snapshot": "^0.*.*",
"nativescript-dev-typescript": "^0.3.0",
"nativescript-dev-sass": "^0.4.1",
"typescript": "^1.8.10"
}
}

Answer 1

Ok found the problem.
<Page.actionBar>
<ActionBar class="action-bar">
<android>
<GridLayout rows="auto" columns="auto,*,auto,auto">
<Label row="0" col="0" text="test"></Label>
</GridLayout>
</android>
<ios>
</ios>
</ActionBar>
</Page.actionBar>
I hadn't defined something for iOS action-bar - that was causing the segmentation fault.
Yes I was planning to add it once I got to the Mac platform.
A simple error message would have been nice.