JavaScript : Object-Oriented Programming

Exercises

1. Look at this code:

   function F() {
     function C() {
       return this;
     }
     return C();
   }
   var o = new F();

   Does the value of this refer to the global object or the object o?

2. What's the result of executing this piece of code?

   function C(){ 
     this.a = 1;
     return false;
   }
   console.log(typeof new C());

3. What's the result of executing the following piece of code?

   > c = [1, 2, [1, 2]];
   > c.sort();
   > c.join('--'); 
   > console.log(c); 

4. Imagine the String() constructor didn't exist. Create a constructor function, MyString(), that acts like String() as closely as possible. You're not allowed to use any built-in string methods or properties, and remember that String() doesn't exist. You can use this code to test your constructor:

   > var s = new MyString('hello'); > s.length; ...