Quiz

Please make sure you select answer in each question, as lack of answer is not checked and counts as failure. The final score is simply a number of wrong answers, less is better. Quiz requires Javascript to be enabled.

1. 1.

   
     (function(){
       return typeof arguments;
     })();
   

   • "object"
   • "array"
   • "arguments"
   • "undefined"
2. 2.

   
     var f = function g(){ return 23; };
     typeof g();
   

   • "number"
   • "undefined"
   • "function"
   • Error
3. 3.

   
     (function(x){
       delete x;
       return x;
     })(1);
   

   • 1
   • null
   • undefined
   • Error
4. 4.

   
     var y = 1, x = y = typeof x;
     x;
   

   • 1
   • "number"
   • undefined
   • "undefined"
5. 5.

   
     (function f(f){
       return typeof f();
     })(function(){ return 1; });
   

   • "number"
   • "undefined"
   • "function"
   • Error
6. 6.

   
     var foo = {
       bar: function() { return this.baz; },
       baz: 1
     };
     (function(){
       return typeof arguments[0]();
     })(foo.bar);
   

   • "undefined"
   • "object"
   • "number"
   • "function"
7. 7.

   
     var foo = {
       bar: function(){ return this.baz; },
       baz: 1
     }
     typeof (f = foo.bar)();
   

   • "undefined"
   • "object"
   • "number"
   • "function"
8. 8.

   
     var f = (function f(){ return "1"; }, function g(){ return 2; })();
     typeof f;
   

   • "string"
   • "number"
   • "function"
   • "undefined"
9. 9.

   
     var x = 1;
     if (function f(){}) {
       x += typeof f;
     }
     x;
   

   • 1
   • "1function"
   • "1undefined"
   • NaN
10. 10.

    
      var x = [typeof x, typeof y][1];
      typeof typeof x;
    

    • "number"
    • "string"
    • "undefined"
    • "object"
11. 11.

    
      (function(foo){
        return typeof foo.bar;
      })({ foo: { bar: 1 } });
    

    • "undefined"
    • "object"
    • "number"
    • Error
12. 12.

    
      (function f(){
        function f(){ return 1; }
        return f();
        function f(){ return 2; }
      })();
    

    • 1
    • 2
    • Error (e.g. "Too much recursion")
    • undefined
13. 13.

    
      function f(){ return f; }
      new f() instanceof f;
    

    • true
    • false
14. 14.

    
      with (function(x, undefined){}) length;
    

    • 1
    • 2
    • undefined
    • Error

?

I hope you liked it. Please leave your score in the comments. I'll try to explain these questions sometime in a near future, unless someone else does it before me.