Javascript Object

Object is used to store multiple values. object has key and value pair.


var obj={name:"John",age:35,sex:"Male"}

You can define multiple objects into the Array. you can say these are Array Object.


var users_details=[{name:"John",age:35,sex:"Male"},
      {name:"Rom",age:30,sex:"Male"},
      {name:"Neena",age:25,sex:"female"}
    ]

define the method into the Object


   var user_details={
     first_name:"John",
     last_name:"Taylor",
     age:35,
     full_name: function() {
       return this.first_name + " " + this.last_name;
   }

   }

Note:- full_name is a method in the user_details Object.

get the Object key value

Suppose you have user_details Object and you want to get the key value


     var user_details={
     first_name:"John",
     last_name:"Taylor",
     age:35,
     full_name: function() {
       return this.first_name + " " + this.last_name;
   }

   }

Example:- get the user’s full_name and age.


console.log(user_details.full_name);
Output:- John Taylor

get the age of the user


console.log(user_details.age);
Output:- 35

Add key value into the Object

Suppose you have user_details Object


 var user_details={
     first_name:"John",
     last_name:"Taylor",
     age:35
   }

Now, you want to add user_id into the user_details Object


 user_details.user_id=1234

Now get the user_details value


console.log(user_details);
Output:-{first_name: “John”, last_name: “Taylor”, age: 35, user_id: 1234}

Try it Yourself

Update key value into the Object

Suppose you have user_details Object


var user_details={
     first_name:"John",
     last_name:"Taylor",
     age:35
   }

Now, you have to update age into the user_details Object


 user_details.age=36

Now get the user_details value


console.log(user_details);
Output:-{first_name: “John”, last_name: “Taylor”, age: 36}

Delete the key value from the Object

Syntax:-


delete object.key

Example:- delete the age key value from the Object


     var user_details={
     first_name:"John",
     last_name:"Taylor",
     age:35
   }

   delete user_details.age;

   console.log(user_details);

Output:-{first_name: “John”, last_name: “Taylor”}

Try it Yourself

Get the Object key value through for in loop

Syntax:- get the Object value


for (var key in Object){
	
 console.log(Object[key]);

}

Example:- Suppose you have users object.


let users={
	id:1,
	first_name:"John",
	last_name:"Taylor",
	age:35
}

Get the users object value


for (var key in users){
	
	console.log(users[key]);

}
Output:-1
John
Taylor
35

Try it Yourself

How to check Object key is exists or not

Syntax:-



object_name.hasOwnProperty(object_key);  //Output true or false

Example:- Suppose you have users object.


let users={
	id:1,
	first_name:"John",
	last_name:"Taylor",
	age:35
}

Now check the key is exists or not


users.hasOwnProperty("first_name");  //Output true

users.hasOwnProperty("email");  //Output false

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How to get the Object’s keys

Syntax:-



Object.keys(object_name);  

Example:- Suppose you have users object.


let users={
	id:1,
	first_name:"John",
	last_name:"Taylor",
	age:35
}

Now you want the all users object keys



Object.keys(users);  

Output:-[“id”,”first_name”,”last_name”,”age”]

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How to get the Object’s values

Syntax:-



Object.values(object_name);  

Example:- Suppose you have users object.


let users={
	id:1,
	first_name:"John",
	last_name:"Taylor",
	age:35
}

Now you want the all users object values



Object.values(users);  

Output:-[1, “John”, “Taylor”, 35]

Try it Yourself