new Operator in Javascript

The new keyword does the following things:

Step 1: Creates a blank, plain JavaScript object;
Step 2: Links (sets the constructor of) this object to another object;
Step 3: Passes the newly created object from Step 1 as the `this` context;
Step 4: Returns this if the function doesn't return an object.

var obj = {
normal: function() {
    this.privatefunction = function() {
        console.log('inside privatefunction', this)
    }
  }
}

var norm = obj.normal() // does nothing
norm.privatefunction() // throws TypeError:
// Cannot read property 'privatefunction' of undefined

var newNorm = new obj.normal()
newNorm.privatefunction() // inside privatefunction normal {privatefunction: ƒ}

The newNorm variable of normal function instantiated with new keyword is able to call privatefunction without an error because of Step 4 (Returns this because normal function returns undefined)