Depromise

It hurts when callbacks executed inside promises throw errors. To avoid the hurt, use a Promise library such as bluebird that provides a .done method.

depromise provides a helper function success that takes a callback function of any arity and returns a function that will call the callback with the proper arguments.

Usage

var depromise = require('depromise');

The usual callback pattern

function fnWithCallback(data, next) {

  var onFailure = next;
  var onSuccess = depromise.success(next);

  promisedFunction(data)
    .then(function(result) {

      // do something with result
      return result

    })
    .done(onSuccess, onFailure)

}

fnWithCallback('foo', function(err, result) {

  // err === null
  // result === 'foo'

});

Callbacks with multiple arguments

Call depromise.success with the optional HAS_MULTIPLE_ARGS flag (true) and return an array containing the arguments for the callback.

function fnWithCallback(data, next) {

  var onFailure = next;
  var onSuccess = depromise.success(next, depromise.HAS_MULTIPLE_ARGS);

  promisedFunction(data)
    .then(function(result) {

      // do something with result
      return [result, 'bar'];

    })
    .done(onSuccess, onFailure)

}

fnWithCallback('foo', function(err, foo, bar) {

  // err === null
  // foo === 'foo'
  // bar === 'bar'

});