enum_x.js

var e;
(function (e) {
    e[e["a"] = 0] = "a";
    e[e["b"] = 1] = "b";
})(e || (e = {}));
var x;
x = 0 /* a */;
console.log(x);
x++;
var y = x++;
console.log(x);
console.log(typeof x);
console.log(y);
console.log(typeof y);

enum_x.ts

enum e {
    a, b
}
var x: e;
x = e.a;
console.log(x); // 0
x++;
var y = x++;
console.log(x); // 2
console.log(typeof x); // number
console.log(y); // 1
console.log(typeof y); // number