proto diff

Author: gambitier

session 1/chapters/3. Prototypes.md

@@ -25,7 +25,37 @@ The constructor property points back to the function on which `prototype` object
 
 ![sharedProto](../images/sharedProto.jpg)
 
-## Prototype Object or Prototype
+# Dunder proto (`__proto__`) vs prototype (`prototype`)
+
+`prototype` is a property of a Function object. It is the prototype or you can say blueprint of objects constructed by that function.
+
+`__proto__` is an internal property of an object, pointing to its prototype. Current standards provide an equivalent Object.getPrototypeOf(obj) method, though the de facto standard `__proto__` is quicker.
+
+**`__proto__` property of an object is a pointer to the object's constructor function's prototype property**
+
+```javascript
+function Foo() {}
+
+const dunderProtoEqualsPrototypeOfFunction =
+	new Foo().__proto__ === Foo.prototype;
+
+const actualObjectDontHavePrototype = new Foo().prototype === undefined;
+
+console.log(
+	'dunder Proto Equals Prototype Of Function',
+	dunderProtoEqualsPrototypeOfFunction
+);
+
+console.log('actual Object Dont Have Prototype', actualObjectDontHavePrototype);
+
+const fooObject = new Foo();
+
+console.log('fooObject is instance of Foo', fooObject instanceof Foo);
+
+console.log('fooObject is instance of Object', fooObject instanceof Object);
+```
+
+# Prototype Object or Prototype
 
 Almost all objects in JavaScript have the prototype property. By using it and more specifically the _prototype chain_ we can mimic inheritance.
 
@@ -99,7 +129,7 @@ console.log(person1.friends); // Output: "Jadeja, Vijay, Amit"
 console.log(person2.friends); // Output: "Jadeja, Vijay, Amit"
 ```
 
-## So What are the Problems?
+# So What are the Problems?
 
 1. Problem with the constructor function: Every object has its own instance of the function
 2. Problem with the prototype: Modifying a property using one object reflects the other object also

session 1/server/index.js

@@ -1,24 +1,17 @@
-//Create an empty constructor function
-function Person() {}
-//Add property name, age to the prototype property of the Person constructor function
-Person.prototype.name = 'Ashwin';
-Person.prototype.age = 26;
-Person.prototype.friends = ['Jadeja', 'Vijay']; //Arrays are of reference type in JavaScript
-Person.prototype.sayName = function () {
-	console.log(this.name);
-};
+function Foo() {}
 
-//Create objects using the Person constructor function
-var person1 = new Person();
-var person2 = new Person();
+const dunderProtoEqualsPrototypeOfFunction =
+	new Foo().__proto__ === Foo.prototype;
 
-//Add a new element to the friends array
-person1.friends.push('Amit');
+const actualObjectDontHavePrototype = new Foo().prototype === undefined;
 
-console.log(person1.friends); // Output: "Jadeja, Vijay, Amit"
-console.log(person2.friends); // Output: "Jadeja, Vijay, Amit"
+console.log(
+	'dunder Proto Equals Prototype Of Function',
+	dunderProtoEqualsPrototypeOfFunction
+);
 
-person1.friends = ['akash'];
+console.log('actual Object Dont Have Prototype', actualObjectDontHavePrototype);
 
-console.log(person1.friends); // Output: "Jadeja, Vijay, Amit"
-console.log(person2.friends); // Output: "Jadeja, Vijay, Amit"
+const fooObject = new Foo();
+console.log('fooObject is instance of Foo', fooObject instanceof Foo);
+console.log('fooObject is instance of Object', fooObject instanceof Object);