Can someone explain this JavaScript code to me?

Question

// Create an object type UserException  
function UserException (message){  
  this.message=message;  
  this.name="UserException";  
}  

// Make the exception convert to a pretty string when used as  
// a string (e.g. by the error console)  
UserException.prototype.toString = function (){  
  return this.name + ': "' + this.message + '"';  
}  

// Create an instance of the object type and throw it  
throw new UserException("Value too high");

How will this be used?

Are you familiar with throwing exceptions? I'm trying to determine what level to explain this at. — Error 454, Dec 28 '10 at 20:47
http://stackoverflow.com/questions/464359/custom-exceptions-in-javascript — jball, Dec 28 '10 at 20:47

score 2 · Accepted Answer · answered Dec 28 '10 at 20:48

2

This is how you can create objects in javascript, in this case, a UserException object with a toString function. It might be used like so:

try {
    throw new UserException("something went wrong");
} catch(ex) {
    console.log(ex);
}

answered Dec 28 '10 at 20:48

Ian Wetherbee

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Can someone explain this JavaScript code to me?

1 Answers1