Javascript Objects and Classes

In Javascript, there are no class declarations in JavaScript.
Javascript objects are dynamic. At runtime, new properties and methods van be add and removed using “delete” operator.
All Javascript properties are public.
Accessing non-existing properties does not throws an exception but returns “undefined”.
Properties can be used in array form, like myObject[myProperty].

Property notation is good for:

  • accessing properties with reserved words or properties starting with numbers (myObject[“1234”], myObj[“new”] works, myObject.1234, does not work)
  • accessing properties dynamicaly (myObject[myVar])

An object can be declared as:
var x = {};

var x = {
a = 1;
b = “string value”;
myMethod() {
return “a”;

is same as:

var x = {}
x.a = 1;
x.b = “string value”;
x.myMethod() {
return “a”;

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