npm install
npm run build

src/database/firebase_list_factory.ts(115,51): error TS2345: Argument of type '(obs: Observer<any[]>) => () => void' is not assignable to parameter of type '(<R>(subscriber: Subscriber<R>) => void | Function | Subscription) | undefined'.
  Type '(obs: Observer<any[]>) => () => void' is not assignable to type '<R>(subscriber: Subscriber<R>) => void | Function | Subscription'.
    Types of parameters 'obs' and 'subscriber' are incompatible.
      Type 'Subscriber<R>' is not assignable to type 'Observer<any[]>'.
        Types of property 'next' are incompatible.
          Type '(value?: R | undefined) => void' is not assignable to type '(value: any[]) => void'.
            Types of parameters 'value' and 'value' are incompatible.
              Type 'any[]' is not assignable to type 'R | undefined'.
                Type 'any[]' is not assignable to type 'R'.