Meteor Async

Set of async utilities to work with NPM modules and other async code blocks.

Installation

meteor add meteorhacks:async

API

Available in the Server Side only

Meteor APIs are executed synchronously. Most of the NodeJS modules works asynchronously. So we need a way to bride the gap. Async Utilities comes to rescue you.

Async.runSync(function)

Async.runSync() pause the execution until you invoke done() callback as shown below.

1var response = Async.runSync(function(done) {
2  setTimeout(function() { 
3    done(null, 1001);
4  }, 100);
5});
6
7console.log(response.result); // 1001

done() callback takes 2 arguments. error and the result object. You can get them as the return value of the Async.runSync() as shown as response in the above example.

return value is an object and it has 2 fields. error and result.

Meteor.sync(function)

Same as Async.runSync but deprecated.

Async.wrap(function)

Wrap an asynchronous function and allow it to be run inside Meteor without callbacks.

1
2//declare a simple async function
3function delayedMessge(delay, message, callback) {
4  setTimeout(function() {
5    callback(null, message);
6  }, delay);
7}
8
9//wrapping
10var wrappedDelayedMessage = Async.wrap(delayedMessge);
11
12//usage
13Meteor.methods({
14  'delayedEcho': function(message) {
15    var response = wrappedDelayedMessage(500, message);
16    return response;
17  }
18});

If the callback has a result, it will be returned from the wrapped function. If there is an error, it will be thrown.

Async.wrap(function) is very similar to Meteor._wrapAsync.

Async.wrap(object, functionName)

Very similar to Async.wrap(function), but this API can be used to wrap an instance method of an object.

1var github = new GithubApi({
2    version: "3.0.0"
3});
4
5//wrapping github.user.getFrom
6var wrappedGetFrom = Async.wrap(github.user, 'getFrom');

Async.wrap(object, functionNameList)

Very similar to Async.wrap(object, functionName), but this API can be used to wrap multiple instance methods of an object.

1GithubApi = Npm.require('github');
2
3var github = new GithubApi({
4    version: "3.0.0"
5});
6
7//wrapping github.user.getFrom and github.user.getEmails
8var wrappedGithubUser = Async.wrap(github.user, ['getFrom', 'getEmails']);
9
10//usage
11var profile = wrappedGithubUser.getFrom({user: 'arunoda'});
12var emails = wrappedGithubUser.getEmails();