objects

Js is all about object

1. creating Objects
2. Factories and construction
3. primitive and reference type
4. working with properties
5. private properties
6. getter and setter

creating Objects

object literals

const a = {}; // these curly brackets are called object literals

const circle={
    radius:4
    location:{
        x:1
        y:2
    }
    draw:function(){

        console.log("draw")
    }
}
circle.draw();

factories function

function createCircle(radius){
 return{
    radius,
    draw:function(){
        console.log("draw")
    }
 }
}
const circle=createCircle(5);
circle.draw();

construction function

// start with capital letter
function Circle(radius) {
  this.radius = radius;
  this.draw = function () {
    console.log("draw");
  };
}
const functionObj = new Circle(1);
// when we invoke a function with "new" keyword;
//three things happen
// 1 new operator will create empty object
// 2 set this to point to this object
// 3 return automatically this object

construction properties

new Object(); // A new Object object
new String(); // A new String object
new Number(); // A new Number object
new Array(); // A new Array object
new Map(); // A new Map object
new Set(); // A new Set object
new Date(); // A new Date object
new RegExp(); // A new RegExp object
new Function(); // A new Function object

// object literals
/*
 but we commonly use object literals instead of creating constructors 
*/

// Use object literals {} instead of new Object().

// Use object literals "",'',``, instead of new String().

// Use array literals [] instead of new Array().

// Use pattern literals /()/ instead of new RegExp().

// Use function expressions () {} instead of new Function().

// every object in js have property called constructor
console.log({}.constructor);

Function are objects

function abc() {}

// abc.apply()
// abc.call(),

// abc.name // name of function
// abc.length // length of parameter passed

working with properties

How to loop keys and values how check if key is present in object

private properties

• how to declare private properties