Javascript Constructors

Question 1

What does the new operator do?

Answer 1

The new operator lets developers create an instance of a user-defined object type or of one of the built-in object types that has a constructor function.

The new keyword does the following things:

Creates a blank, plain JavaScript object.
Sets objects protoype to be prototype of constructor
calls p
Binds the newly created object instance as the this context (i.e. all references to this in the constructor function now refer to the object created in the first step).
Returns this if the function doesn’t return an object.

Question 2

What property of JavaScript functions can store shared behavior for instances created with new?

Answer 2

function.prototype

Question 3

What does the instanceof operator do?

Answer 3

The instanceof operator tests to see if the prototype property of a constructor appears anywhere in the prototype chain of an object. The return value is a boolean value.