JSFiddle - React, Tailwind, and code Playground

JavaScript

function newObj(){
     this.v1 = 10;
     this.v2 = 20;
     this.func1val = (function(){ alert('called from c\'tor'); })();
     this.func2val = (function(){ return 2 + 1; })();
 }
 
 var temp = new newObj();
 alert('temp.func2val = ' + temp.func2val);