Question

Somehow this does not feel like the culmination of the 50 years programming language development:

  throw "My exception message here";

What’s the correct way to do exceptions in Javascript, so that

• They can be identified (instanceof)

• They can carry other payload besides the default message and stack trace

• They “subclass” base Exception, so that debug console and such can extract meaningful information about the exception

• Possible nested exceptions (converting exception to another): if you need to catch an exception and rethrow new one the orignal stack trace would be preserved and could be meaningfully read by debugging tools

• They follow Javascript best practices

Answer 1

throw new Error("message");

or if you want to be more specific use one of the Error Objects

It’s important to make sure you throw real errors because they contain the stack trace. Throwing a string is stupid because it doesn’t have any meta data attached to it.

You can also subclass errors

// for some sensible implementation of extend 
// https://gist.github.com/1441105#file_1pd.js
var MyError = extend(Object.create(Error.prototype), {
   ...
});