async-utils

Node complementary utils for Caolan async's module

applyIE (as in apply Ignore Errors)

Caolan's async.apply method that ignore errors and yields undefined. WARNING: this only works for callback ending argument functions which are standard with async so it should be ok. It helps to stop async to cancel tasks if one fails

Example:

var asyncUtils = require('async-utils');

var yield_error = function(name, cb) {
  //name === 'tom'
  cb(new Error('ignored error');
};

var applied_fx = asyncUtils.applyIE(yield_error, 'tom');

applied_fx(function(error) {
  //error is undefined
  //continue processing after ignoring the error
});

intercept (as in intercept error callbacks)

Callback interceptor to avoid one line error check ifs

Example:

var asyncUtils = require('async-utils');

var yield_error = function(cb) {
  cb(new Error('yielded error');
};

function process(callback) {
  yield_error(asyncUtils.intercept(callback, function() {
    //this code never get executed, instead callback was called with yielded error
  }));
}

applyAuto (as in apply to use in async.auto)

Change function interface from node standard to async.auto function interface

Async.auto handles functions with this signature:

function(callback, results)

This method changes this into this one automagically

function(result1, [,..], callback)

Example:

var async = require('async');
var asyncUtils = require('async-utils');

var flow = {
  step1: someFx,
  withoutApplyAuto: ['step1', function(cb, results) {
    //get step1 value
    var step1 = results.step1;
    //work with step1
    return cb();
  }],
  withApplyAuto: asyncUtils.applyAuto(['step1', function(step1, cb) {
    //work with step1 directly as an argument
    return cb();
  }]),
};

async.auto(flow, function endFlow(error, results) {});

pluck (as in pluck and callback)

Get a property from an async op yielded response and callback with it It's safe, so if the property is not available it yields null. It's intercepted, so if the async op yields an error it forwards the same error

Example:

var asyncUtils = require('async-utils');

var op = function(cb) {
	return cb(undefined, {
		msg: 'level 0',
		l1: {
			msg: 'level 1',
			l2: {
				msg: 'level 2',
				l3: {
					msg: 'level 3',
					array: ['primero']
				}
			}
		}
	});
};


op(asyncUtils.pluck('l1.l2.l3.array[0]', function cb(error, deepL3ArrayFirstElem) {
	console.log('e: ', error);
	console.log('resp: ', deepL3ArrayFirstElem);
}));

fuse (as in fuse my callback)

Adds a fuse timeout for callbacks. Implements a timeout where if callback has not been called by n ms, then it gets callback'ed by async-utils with an error

Example:

var asyncUtils = require('async-utils');

var getTimedCb = function(ms, response) {
  return function(cb) {
    setTimeout(function() {
      cb(undefined, response);
    }, ms);
  };
};

var asyncFx = getTimedCb(50, undefined, 'ok');
    
asyncFx(asyncUtils.fuse(10, function(error, response) {
  console.log(response); //undefined
  console.log(error); //async-utils fuse timeout rechead!
}));