Exception

NodObjC makes it seamless to catch Objective-C exceptions, using the standard JavaScript try/catch syntax you are already familiar with.

When an Objective-C method or function throws an NSException, you can catch the exception and inspect it further. The error object that gets passed can be invoked to send messages, just like any other Objective-C object in NodObjC. The error object also has it's message and stack properties set, so that you can easily retrieve the error message and get a dump of the stack trace.

var array = $.NSMutableArray('alloc')('init')

try {

  // This will throw an exception since you can't add a null pointer
  array('addObject', null)

} catch (err) {

  err('name')
  // 'NSInvalidArgumentException'

  err('reason')
  // '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'

  err('reason') == err.message
  // true

  err.stack
  // NSInvalidArgumentException: *** -[__NSArrayM insertObject:atIndex:]: object cannot be nil
  //     at Function.msgSend (/Users/nrajlich/NodObjC/lib/id.js:139:21)
  //     at id (/Users/nrajlich/NodObjC/lib/id.js:105:15)
  //     at Object.<anonymous> (/Users/nrajlich/NodObjC/array-exception.js:8:3)
  //     at Module._compile (module.js:411:26)
  //     at Object..js (module.js:417:10)
  //     at Module.load (module.js:343:31)
  //     at Function._load (module.js:302:12)
  //     at Array.0 (module.js:430:10)
  //     at EventEmitter._tickCallback (node.js:126:26)

}

wrap()

This is a private function used internally by NodObjC. You should not need to use this function in your code.

Wraps a Pointer that should be an Objective-C NSException instance.

function wrap (pointer) {
  var w = id.wrap(pointer)
  w.__proto__ = proto
  // `name` is non-configurable on Functions, so don't bother
  w.message = String(w('reason'))
  Error.captureStackTrace(w, wrap)
  return w
}

Exception#toString()

A toString() override that mimics an Error object's toString(), using the equivalent Objective-C NSException instance methods.

// `err` is a caught NSException instance
err.toString()
// 'NSInvalidArgumentException: *** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'

proto.toString = function toString () {
  return this('name') + ': ' + this('reason')
}

NodObjC

The NodeJS ⇆ Objective-C Bridge

Exception

wrap()

Exception#toString()