It returns true if the specified property is enumerable otherwise return false. It returns true if the specified object is in the prototype chain of the object this method is called upon otherwise return false. It returns true if an object contains the specified property as a direct property of that object and not inherited through the prototype chain otherwise returns false. With prototype approach constructor function will be loaded in memory once and every new object will share the same instance of the function. Prototype property has constructor property by-default. When a function is created, a prototype property is added to it by JavaScript engine. It is not a good idea to have multiple copies of same function which are doing same thing. It is thus known as prototype based language.Įvery time when a new object is created with constructor function, it has its own copy of constructor function with all properties and methods. In JavaScript, each object contains a prototype object and the prototype property is added to each function automatically when created. A first or preliminary version of a device or vehicle from which other forms are developed.Ī prototype-based language is one that facilitates the objects to obtain properties and features from one another.

Javascript prototype