synchronize-helpers
v0.1.0
Published
A module providing commonly used helpers for synchronize.js callbacks
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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.