Im new to Node js language In most of the Node js sample app all are using prototype.Then i came to know using prototype we can add the methods and properties into an object.Still i'm not clear about what is the use of prototype.Can anyone explain me.
In short, prototype is used to build the interface (and implementation) of your custom-build objects in JavaScript.
As said Blender in the comment, it's how you do real OOP in JavaScript.
Using a prototype will also mean that you can define a method in one place (low memory footprint). Not defining a method via a prototype means that the method is defined for each instance of said object (high memory footprint).