Which one of the following defines properties for the map? 

What is the output of the following JavaScript code?

var x;
window.alert(x);

Which React Router component is used to define the route matcher?

Which of the following are types of errors in JavaScript?

 The type of a variable that is volatile is ______________ 

Which method to use to get a particular value using the tagged value?

What is the output of the following JavaScript code?

[1, 2, 3].map(function(n) {
   return !(n > 1) ? 1 : arguments.callee(n - 1) * n;
});

Which of the following is the correct way of initializing an array?

 One of the special features of an interpreter in reference with the for loop is that ___________ 

What is a reducer in the context of state management?