Why does this trigger an Identifier Expected error in Typescript?

Question

The second line in this statement causes an error. I understand if I wrap the lambda in parentheses it solves the problem as in the first line. I'm just curious why it is an error, as in JavaScript a lambda there would work fine.

var okay = true && (() => {});
var fails = true && () => {};

Answer 1

It is a precedence issue:

var fails = true && () => {};
                  // <-- Error: Expression expected

... is equivalent to:

var fails = (true && ()) => {};