Deserializing optional nested fields

[prudnikov]

Cerialize version 2.0.1

Here is example code:

    class TestNested {
      @deserializeAs(Number) id: number;
    }
    class TestModel {
      @deserializeAs(Number) id: number;
      @deserializeAs(TestNested) n: TestNested;
    }

    const data1 = {id: 1, n: {id: 2}};
    const data2 = {id: 1, n: null};
    console.log('Data1', Deserialize(data1, TestModel));
    console.log('Data2', Deserialize(data2, TestModel));

Second deserialization is failing with error while first is ok.

MyComponent_Host.ngfactory.js? [sm]:1 ERROR TypeError: Cannot read property 'id' of null
    at _Deserialize (deserialize.js:124)
    at _Deserialize (deserialize.js:139)
    at Deserialize (deserialize.js:159)
   // ... remaining stack trace

Is there any way to deserialize optional nested field? Or should I write a custom SerializeFn?