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Object Basics

JavaScript is an object-oriented language. JavaScript treats everything as an object. Object is an unordered list with a collection of primitive data types, functions and even with other objects. A javaScript object is an entity having key and value. JavaScript is a template-based language, not a class-based language. To obtain the object, we do not create a class. But we direct the creation of objects.

Work out​

var person = {
  firstName: "John",
  lastName: "Rice",
  Age: 27,
  DOB: "01-01-2000",
};

console.log(person);
// expected output: { firstName: "John", lastName: "Rice", age: 27, DOB: "01-01-2000" }

Creating Objects in JavaScript​

There are 3 ways to create objects:

  • By using object literal
  • By creating an instance of the object by using new keyword
  • By using an object constructor

Creating object using object literal​

Syntax​

The syntax for creating objects using object literal method is

object = { property1: "value1", property2: "value2", property3: "value3"}

Example​

var student = {
  name: "Sara David",
  standard: 10,
  school: "ABC School",
};
console.log(student);
// expected output: { name: "Sara David", standard: 10, school: "ABC School" }

Creating object using new keyword​

Syntax​

The syntax for creating a new object using the new keyword is

var objectName = new Object();
let objectName = new Object();

The new keyword is used to create a new object.

Example​

var student = new Object();
student.name = "Sara David";
student.standard = 10;
student.school = "ABC School";

console.log(student);
// expected output: { name: "Sara David", standard: 10, school: "ABC School" }

Creating object using constructor​

The this keyword is used to create a new object. A function is created and arguments passed as argument to this function is assigned to the object using this keyword.

Example​

function student(name, standard, school) {
  this.name = name;
  this.standard = standard;
  this.school = school;
}
var student1 = new student("Sara David", 10, "ABC School");
console.log(student1);
// expected output: student { name: "Sara David", standard: 10, school: "ABC School" }