What is prototype in js?

 In JavaScript, a prototype is an object that acts as a template for creating new objects. Each object in JavaScript has a prototype, which is another object. When you create a new object, it inherits properties and methods from its prototype.

When you access a property or method of an object, JavaScript first checks if the property or method exists on that object. If it doesn't, it will look for the property or method on the object's prototype. This process continues until it finds the property or method or reaches the end of the prototype chain.

You can think of prototypes as a way of adding methods and properties to an object without modifying its existing structure. This allows for a more efficient and flexible way of defining and reusing functionality.

It's also possible to change the prototype of an object, this is known as prototypal inheritance, it allows you to create a new object with the same properties and methods of an existing object and later on you can add new properties or methods to the new object or change the existing ones.

In summary, prototypes in JavaScript provide a mechanism for sharing properties and methods among objects, and they are a key aspect of the language's object-oriented nature.

Here is an example of using prototypes in JavaScript:

 // Define a prototype object with a property and a method
    let animalPrototype = {
        species: "unknown",
        say: function() {
        console.log("I am a " + this.species);
        }
    };
    // Create a new object that inherits from the prototype
    let dog = Object.create(animalPrototype);
    dog.species = "dog";
    // The dog object has access to the properties and methods of the prototype
    dog.say(); // Output: "I am a dog"
    console.log(dog.species); // Output: "dog"