When Should I Use new Object() vs. Object Literal Notation in JavaScript?

Object Creation in JavaScript: new Object() vs. Object Literal Notation

The practice of creating objects in JavaScript can involve two common approaches: the constructor-based syntax using new Object() and the object literal notation. While both methods appear to yield similar results, there is a distinction to be made.

Constructor-based Syntax (via new Object()):

This approach involves instantiating a new object using the new keyword and the Object() constructor, as seen in the first example code:

person = new Object()

Object Literal Notation:

In contrast, the object literal notation provides a concise way to define objects directly within curly braces, as demonstrated in the second example code:

person = {
    property1 : "Hello"
};

Differences in Method Definition:

The key difference between these two approaches manifests when incorporating methods into objects.

Using Object Literals (Disadvantages):

When defining methods within object literals, each object instance carries its own copy of the method, leading to memory overhead, especially when working with numerous objects or methods.

function Obj( prop ) { 
    return { 
        p : prop, 
        sayHello : function(){ alert(this.p); }, 
    }; 
} 

var foo = new Obj( "hello" ); // creates a new instance of Obj

Using new Object() with Prototypal Inheritance (Advantages):

With the constructor-based syntax, methods can be defined on the object's prototype, allowing all instances to share the same method. This approach conserves memory and is particularly beneficial when managing large object sets or complex method hierarchies.

function Obj( prop ) { 
    this.p = prop; 
} 
Obj.prototype.sayHello = function(){alert(this.p);}; 

var foo = new Obj( "hello" ); // creates a new instance of Obj

Conclusion:

In simple scenarios where objects lack methods, both approaches perform similarly. However, when working with objects that require methods, the constructor-based syntax with prototypal inheritance emerges as the superior choice, offering significant memory savings and efficient code organization.

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