1function A() {
2  this.val = "Error";
3  (function() {
4    this.val = "Success";
5  })();
6}
7
8function B() {
9  this.val = "Error";
10  (() => {
11    this.val = "Success";
12  })();
13}
14
15var a = new A();
16var b = new B();
17a.val // "Error"
18b.val // "Success"