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JavaScript Object-Oriented JavaScript (2015) Constructor Functions and Prototypes Methods with Prototypes

Posted by Andrei Li
Andrei Li
34,475 Points

What is the practical application of Prototype? Why do we need Prototype in programming?

In previous courses I saw Prototype in JavaScript library. Does it mean that Prototype just extended by methods in JavaScript API? Or there is a something else.

1 Answer

Andrey Misikhin
Andrey Misikhin
16,529 Points
Andrey Misikhin
Andrey Misikhin
16,529 Points

For example, if you add function (method) into your class, then this function will be created every time for every instance of this class, even if you don't use it and it takes up more memory. If you add this function to prototype of your class, then will be used only one instance of this function for all objects of the class. Another feature, that you may create addition functionality of all existing objects of your class with just adding method into prototype of the class. And the main appointment, that inheritance in JS, under the hood, works through prototype.proto and new ES6 syntax for creating classes and inheritance is just "syntactic sugar".