Question: How to get the the generic type of Array?

The requirement is to create obj by generic type.  
```typescript
class A { }
function createObj<T>(): T {
    var isArr = isArray<T>();
    if (isArr) {
        let arr = {} as T;
        // Is there a way to create an instance of A and push the instance to the `arr`
       return arr;
    }
    // other logic
}
createObj<Array<A>>();
```