[recursive]

I have no idea about the lawyerly technicalities, but you can try it yourself to verify what I'm saying.

https://flow.org/try/

Compare these two programs.

    const arr = ["abcd"];
    const str = arr[1];
    const num = str.length; // this throws at runtime

    const arr = [new Date];
    const dt = arr[1];
    const num = dt.length; // fails to type check