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Sun Jun 13 2021 15:38:33 GMT+0000 (Coordinated Universal Time)

Saved by @jpannu #angular #typescript 

   /*
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    ** Pending **
  -Methods:
call(), apply(), bind()



  **

  Book :> The Principle of Object oriented Javscript

    **
   : Dereferencing Objects //Is used to Clear the memory on browser           engine.
var object1 = new Object();
// do something
object1 = null;
    // dereference  
   **
    
    **
    : Deleting a value from Object.
    > delete objName.key;
    **
      
    **
    : Function Example -
  function reflect(value) {
    return value;
  }
// is the same as
var reflect = new Function("value", "return value;"); 
     **
        
      **
  arrName['push']('3'); //This is also valid ( using bracket              notation )
       **

      ** // It will store the values as an Object ( String ).
  let nameVariable = new String();
nameVariable.fname = 'Karan';
nameVariable.lname = 'Singh';
       **
           
       ** hasOwnProperty **
    let obj = { fname: "Karan", lname: "Singh" }

    > console.log('fname' in obj)  //true
    > console.log('lname' in obj) //true

    > console.log('toString' in obj)  //true 
    // ( Inbuilt methods will also return true )

    > console.log(obj.hasOwnProperty('toString')) //False
    **
           
       **
           //Ways to access Properties in Object
         > Object.keys(objName); //Will return keys
         > Object.values(objName); //Will return values 
  
       **
       //To check if Properties are Enumerable                                                (propertyIsEnumerable).
    > (objName.propertyIsEnumerable(key)); //true or false

      Object.defineProperty(obj, prop, descriptor) //Syntax
       **
        //We can change the default state of the Object.

        var person1 = {};
       **
      Object.defineProperty(person1, "name", {
        value: "Nicholas",
        enumerable: true,
        configurable: true,
        writable: true
      }); //It will create 'name' in person1 Object with 'descriptor'.

      Object.defineProperty(person1, "name", {
      enumerable: false
      }); //We can define in Single Lines as well ( Depending upon our need )

      Object.defineProperty(person1, 'property1', {
        value: 42,
        writable: false
      });// 'property1' can not be overwritten.


      **
     //Preventing Object Modification      
       //Syntax
      > Object.preventExtensions(person1); //false
            /*It will not allow to add new properties to object 'person1'.
            */
      //isExtensible() (How to check?)
      > console.log(Object.isExtensible(obj)); //It will tell whether it's               extensible or not ( true / false )

**
       //Freezing the Object. ( Cant not add/remove. ( read-only ) )
        > Object.feeze(objName);

        //isFrozen() ( How to Check? )
       > console.log(Object.isFrozen(objName)); //Will return true or false.


   ** //Three methods which does not allow mathods to add/remove properties.
        > Object.preventExtensions(objName)
        > Object.seal(objName)
        > Object.freeze(objName)
        //To how to check, Use these methods.   
        console.log(Object.isExtensible(person1));
        console.log(Object.isSealed(person1));
        console.log(Object.isFrozen(person1));



     **//Using Prototypes with Constructors

          function Person(name){
            this.name = name;
          }

          Person.prototype.sayName = function(){
            return this.name;
          }

          let karan = new Person("Jaskaran");













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