At time of writing, TypeScript does not support the optional chaining operator. See discussion on the TypeScript issue tracker: https://github.com/Microsoft/TypeScript/issues/16
As a warning, the semantics of this operator are still very much in flux, which is why TypeScript hasn't added it yet. Code written today against the Babel plugin may change behavior in the future without warning, leading to difficult bugs. I generally recommend people to not start using syntax whose behavior hasn't been well-defined yet.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
