Javascript: Object

Object

an object is a collection of properties and their values. properties and values come always in pairs and called key-value pairs. Key-value pair is known as Name value pair

creating an object

var obj = new Object(); //constructor method calls function. It calls the constructor of obj 

var obj1 = { } //object literal method and braket notation

var student = {

      name: 'sinuna',

      phoneNumber: 83218936213,

      class: 8,
      section:'c',

      present:false,
      address: {
           permanent:'ktm',

            temp: 'bir'
}

}

student.class = 9;

student.getAddress = function(){

}

console.log('student is inital>', student);

student.eduction = 'masters'; //Data added for sudent object

student.abc = {} //object added for student object

console.log('student is final>', student);

console.log('student name is>', student.name); Output: student name is sinuna

Replacing section value

student.section = 'd'; // d searches for reference so 'd' (with brackes) is used

deleting property of Object

delete student.present;

console.log('student after delete', student);

accessing object properties

1. . (dot notation) eg: console.log('student dot notation > ', student.name);

2. [] (bracket notation) eg: console.log('sudent bracket notation>', student['name']);

bracket notation mostly used in the loop

Data insert in Object

var classRoom = {};

console.log('class at inital', classRoom);

classRoom.length = '9m'; classRoom is identifier and length is property hold and 9m is value

classRoom.width = '8m';

classRoom.fan = true;

classRoom.number = 9;

console.log('class at final', classRoom);

Note: camel casing eg: phoneNumber ->1st letter small and 2nd letter capital