Implementing a simple function on typescript to call a Firebase callable function is not working.
Using firebase-tools@4.0.3 -g, firebase-functions@2.0.5, firebase@5.3.1

Firebase callable function:

```
import * as functions from "firebase-functions";

exports.httpsOnCall = functions.https.onCall((data, context) => {
  console.log(data);
  return data;
});

```

It is deployed correctly

Calling the function in webapp:

```
const a = Firebase.functions.httpsCallable("httpsOnCall");
  a.call({ a: 1, b: "testing", c: true }).then(result => {
    console.log(result);
  });

```

Firebase object initialization:

```
import * as firebase from "firebase";

const config = {
  apiKey: "asdasdasd",
  authDomain: "APPNAME.firebaseapp.com",
  databaseURL: "https://APPNAME.firebaseio.com",
  projectId: "APPNAME",
  storageBucket: "APPNAME.appspot.com",
  messagingSenderId: "123456"
};
firebase.initializeApp(config);
const Firebase = {
   functions: firebase.functions()
}

```

Log from firebase:

```
null

```

Log from webapp:

```
{data: null}

```

It seems like data is not reaching the httpsOnCall function, even though the context variable is populated.