https://github.com/marcello3d/node-waiter

A simple way to wait for multiple asynchronous calls to return in Node.js.
https://github.com/marcello3d/node-waiter

Last synced: 15 days ago
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A simple way to wait for multiple asynchronous calls to return in Node.js.

• Host: GitHub
• URL: https://github.com/marcello3d/node-waiter
• Owner: marcello3d
• License: zlib
• Created: 2011-04-11T02:31:04.000Z (over 13 years ago)
• Default Branch: master
• Last Pushed: 2011-04-13T01:36:42.000Z (over 13 years ago)
• Last Synced: 2024-10-28T10:05:45.143Z (19 days ago)
• Language: JavaScript
• Homepage: https://github.com/marcello3d/node-waiter
• Size: 93.8 KB
• Stars: 4
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: Readme.md
  • License: LICENSE

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README

        
node-waiter

===========

A simple way to wait for multiple asynchronous calls to return in Node.js.

Introduction

------------

Just a little utility class I wrote for dealing with parallel code. It lets you spin off a bunch of asynchronous

operations and wait for them to finish.

Waiter is similar to other projects like [Step][1], [async][2], and [Seq][3], but with a focus on parallel operations

that return values.

Examples

--------

Read three files asynchronously.

    var waiter = new Waiter

    var aFile = waiter(),

        bFile = waiter(),

        cFile = waiter()

    fs.readFile('a.txt', aFile)

    fs.readFile('b.txt', bFile)

    fs.readFile('c.txt', cFile)

    // wait for them to finish

    waiter.waitForAll(function(error) {

        if (error) {

            // inspect individual errors in aFile.error, bFile.error, and cFile.error

            throw "oh no!"

        }

        // do something with aFile.value, bFile.value, and cFile.value

    })

You can call waiter() as many times as you want --- but call them all before calling waitForAll!

    var files = [ ... ]

    var waiter = new Waiter

    var filesContent = files.map(function(file) {

        // Alternative syntax, pass a function into waiter(), and get the callback as an argument

        return waiter(function(done) {

            fs.readFile(file,done)

        })

    })

    waiter.waitForAll(function(error) {

        // do something with error or fileContents[x].value

    }, 2000) // optional timeout parameter

Don't care about the values? You don't have to store the result of waiter():

    var waiter = new Waiter

    fs.writeFile('a.txt', 'hello a!', waiter())

    fs.writeFile('b.txt', 'hello b!', waiter())

    fs.writeFile('c.txt', 'hello c!', waiter())

    waiter.waitForAll(function(error) {

        if (error) {

            console.error("Oh no!", error)

        } else {

            // all files have been written successfully!

        }

    })

Alternative syntax if you don't care about the values:

    new Waiter(

        function(done) {

            fs.writeFile('a.txt', 'hello a!', done)

        },

        function(done) {

            fs.writeFile('b.txt', 'hello b!', done)

        }

    ).waitForAll(function(error) {

        // same old...

    })

License

-------

Waiter is open source software under the [zlib license][1].

[1]: https://github.com/creationix/step

[2]: https://github.com/caolan/async

[3]: https://github.com/substack/node-seq

[4]: https://github.com/marcello3d/node-mongolian/blob/master/LICENSE