npm:synchronize-helpers

README

synchronize-helpers

This module provides helpers for wrapping sync.defer() for synchronize.js. wrapException is used to ensure that we won't throw an exception in a sync.parallel block which would otherwise halt processing of the block. While swallowException is useful to swallow any exceptions that would otherwise be thrown (when we'd rather handle the returned data as undefined vs try/catch which can be useful if in a sync.parallel block where we expect certain errors can occur).

Install

$ npm install synchronize-helpers --save

API

wrapException(done, errArray)

A common pattern is to use a parallel block from synchronize to run code concurrently. wrapException allows you to defer error handling until the end by providing an error to hold all exceptions that occur.

var sync = require('synchronize');
var wrapException = require('synchronize-helpers').wrapException;
var thrownErrors = [];

sync.parallel(function() {
  doA(wrapException(sync.defer(), thrownErrors));
  doB(wrapException(sync.defer(), thrownErrors));
  doC(wrapException(sync.defer(), thrownErrors));
});

sync.await();

console.dir(thrownErrors);

swallowException(done)

There is also the situation where one might be retrieving data, and instead of handling any errors, would rather consider the data to be undefined. A concrete case would be retrieving instance metadata but not wanting to write conditional code for determining whether the environment was production, staging, dev, testing, etc. As such, we could do the following:

var sync = require('synchronize');
var swallowException = require('synchronize-helpers').swallowException;

sync.parallel(function() {
  doA(swallowException(sync.defer()));
  doB(swallowException(sync.defer()));
  doC(swallowException(sync.defer()));
});

var data = sync.await();
console.dir(data);

Release History

1.0.0 Initial release.

Usage no npm install needed!