Node.js Tutorial - Node.js Objects

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To create an object, we can use either of the following,

var o1 = new Object();
var o2 = {};

The latter, known as object literal syntax, is preferred.

We can specify the contents of objects using object literal syntax.

We can specify member names and values at initialization time:

Example

var user = {
     first_name: "HTML",
     last_name: "CSS",
     age: 32,
     website: "java2s.com"
};

We can add a new property to your user object by using any of the following methods:

user.name= "brown";
user["name"] = "brown";
var attribute = 'name';
user[attribute] = "brown";

If we try to access a property that does not exist, we do not receive an error, but instead just get back undefined.

To remove a property from an object, we can use the delete keyword:

delete user.name;

Object Literals

The most common way of creating an object in JavaScript is using the object notation, {}.

Objects can be extended arbitrarily at runtime.

var myData = {}; 
console.log(myData); // {} 

myData.myValue = 123; // extend myData 
console.log(myData); // { myValue: 123 } 

The code above generates the following result.

We can define which properties go on an object upfront by using the object literal notation.

var myData = { 
    myValue: 123 
}; 
console.log(myData); // { myValue: 123 } 

The code above generates the following result.

We can nest object literals inside object literals.

var myData = { 
    myValue: 123, 
    bas: { 
        bas1: 'some string', 
        bas2: 345 
    } 
}; 
console.log(myData); 

We can have arrays inside object literals.

var myData = { 
    myValue: 123, 
    bas: [1, 2, 3] 
}; 
console.log(myData); 

We can also have these arrays themselves contain object literals.

var myData = { 
    myValue: 123, /*from   w ww  .j a  v  a 2  s .  co m*/
    bas: [{ 
            myItem: 1 
          }, 
          { 
            myItem: 2 
          }, 
          {
            myItem: 3
    }] 
}; 
console.log(myData.myValue); // 123 
console.log(myData.bas[0].myItem); // 1 
console.log(myData.bas[2].myItem); // 2 

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