callbacks-have-no-built-in-error-handling-mechanism.js

// this doesn't work
try {
  httpGet(function callback() {
    // an error caused asynchronously
    // cannot be caught via a callback
    // mechanism
  }) 
} catch (err) {
  // this will only get called if httpGet
  // itself throws a synchronous error
  // but not if our callback throws an
  // error instead.
}