How to access private variable using a public method within same object in javascript?

Question

I am trying to understand Encapsulation through this link

function Test() {
  var prop1 = "one";
  this.prop2 = "two";

  function meth1() {
    console.log("Inside meth1" + prop1);
  }

  this.meth2 = function() {
    console.log(this.prop2 + "................, " + meth1());
  };

  this.meth4 = function(val) {

    prop1 = val;

    console.log("inside meth4" + prop1);
  }
}

var tc = new Test();
var result1 = tc.meth2();
var result3 = tc.prop1;

According to the link meth1() accessed through this.meth2 should work, but to my surprise i got undefined.

Could you please shed some light on what is happening here. I am using IE 9 for this and getting

LOG: Inside meth1one 
LOG: two................, undefined 

Answer 1

in addition to @Michael's answer, when you try to make a function as a class, remember to return value. This value will be publicly available. In a class structure, var result3 = tc.prop1; should return undefined. Only way to access it should be a function. Following is a representation

function Test() {
  
  // To hold context as object inside functions
  var self = this;
  self.prop1 = "one";
  self.prop2 = "two";

  // method to access prop1
  function meth1() {
    return self.prop1;
  }

  // method to access prop2
  function meth2() {
    return self.prop2;
  };
  
  // Properties that will be publically available.
  // Never add private variables here.
  return{
    "meth1":meth1,
    "meth2":meth2
  }
}

var tc = new Test();
var result1 = tc.meth1(); // Should be "one"
var result2 = tc.prop1;   // Should be "undefined". Private property
var result3 = tc.meth2(); // Should be "two"

console.log(result1,result2,result3)