Are you referring to a case like this?

    {
      f();
      var a = 3;
      function f() {
        console.log(a);
      }
    }

That will print "undefined" because the entire function f() is hoisted and callable in the first line, but the variable a has not yet been assigned the value. That's not a race condition (those are related to timing in concurrent systems) but is certainly the sort of counter-intuitive visibility that makes me prefer to use function expressions most of the time.