# Async.js
[![Build Status via Travis CI](https://travis-ci.org/caolan/async.svg?branch=master)](https://travis-ci.org/caolan/async)
Async is a utility module which provides straight-forward, powerful functions
for working with asynchronous JavaScript. Although originally designed for
use with [Node.js](http://nodejs.org), it can also be used directly in the
browser. Also supports [component](https://github.com/component/component).
Async provides around 20 functions that include the usual 'functional'
suspects (`map`, `reduce`, `filter`, `each`…) as well as some common patterns
for asynchronous control flow (`parallel`, `series`, `waterfall`…). All these
functions assume you follow the Node.js convention of providing a single
callback as the last argument of your `async` function.
## Quick Examples
```javascript
async.map(['file1','file2','file3'], fs.stat, function(err, results){
// results is now an array of stats for each file
});
async.filter(['file1','file2','file3'], fs.exists, function(results){
// results now equals an array of the existing files
});
async.parallel([
function(){ ... },
function(){ ... }
], callback);
async.series([
function(){ ... },
function(){ ... }
]);
```
There are many more functions available so take a look at the docs below for a
full list. This module aims to be comprehensive, so if you feel anything is
missing please create a GitHub issue for it.
## Common Pitfalls
### Binding a context to an iterator
This section is really about `bind`, not about `async`. If you are wondering how to
make `async` execute your iterators in a given context, or are confused as to why
a method of another library isn't working as an iterator, study this example:
```js
// Here is a simple object with an (unnecessarily roundabout) squaring method
var AsyncSquaringLibrary = {
squareExponent: 2,
square: function(number, callback){
var result = Math.pow(number, this.squareExponent);
setTimeout(function(){
callback(null, result);
}, 200);
}
};
async.map([1, 2, 3], AsyncSquaringLibrary.square, function(err, result){
// result is [NaN, NaN, NaN]
// This fails because the `this.squareExponent` expression in the square
// function is not evaluated in the context of AsyncSquaringLibrary, and is
// therefore undefined.
});
async.map([1, 2, 3], AsyncSquaringLibrary.square.bind(AsyncSquaringLibrary), function(err, result){
// result is [1, 4, 9]
// With the help of bind we can attach a context to the iterator before
// passing it to async. Now the square function will be executed in its
// 'home' AsyncSquaringLibrary context and the value of `this.squareExponent`
// will be as expected.
});
```
## Download
The source is available for download from
[GitHub](http://github.com/caolan/async).
Alternatively, you can install using Node Package Manager (`npm`):
npm install async
__Development:__ [async.js](https://github.com/caolan/async/raw/master/lib/async.js) - 29.6kb Uncompressed
## In the Browser
So far it's been tested in IE6, IE7, IE8, FF3.6 and Chrome 5.
Usage:
```html
<script type="text/javascript" src="async.js"></script>
<script type="text/javascript">
async.map(data, asyncProcess, function(err, results){
alert(results);
});
</script>
```
## Documentation
### Collections
* [`each`](#each)
* [`eachSeries`](#eachSeries)
* [`eachLimit`](#eachLimit)
* [`map`](#map)
* [`mapSeries`](#mapSeries)
* [`mapLimit`](#mapLimit)
* [`filter`](#filter)
* [`filterSeries`](#filterSeries)
* [`reject`](#reject)
* [`rejectSeries`](#rejectSeries)
* [`reduce`](#reduce)
* [`reduceRight`](#reduceRight)
* [`detect`](#detect)
* [`detectSeries`](#detectSeries)
* [`sortBy`](#sortBy)
* [`some`](#some)
* [`every`](#every)
* [`concat`](#concat)
* [`concatSeries`](#concatSeries)
### Control Flow
* [`series`](#seriestasks-callback)
* [`parallel`](#parallel)
* [`parallelLimit`](#parallellimittasks-limit-callback)
* [`whilst`](#whilst)
* [`doWhilst`](#doWhilst)
* [`until`](#until)
* [`doUntil`](#doUntil)
* [`forever`](#forever)
* [`waterfall`](#waterfall)
* [`compose`](#compose)
* [`seq`](#seq)
* [`applyEach`](#applyEach)
* [`applyEachSeries`](#applyEachSeries)
* [`queue`](#queue)
* [`priorityQueue`](#priorityQueue)
* [`cargo`](#cargo)
* [`auto`](#auto)
* [`retry`](#retry)
* [`iterator`](#iterator)
* [`apply`](#apply)
* [`nextTick`](#nextTick)
* [`times`](#times)
* [`timesSeries`](#timesSeries)
### Utils
* [`memoize`](#memoize)
* [`unmemoize`](#unmemoize)
* [`log`](#log)
* [`dir`](#dir)
* [`noConflict`](#noConflict)
## Collections
<a name="forEach" />
<a name="each" />
### each(arr, iterator, callback)
Applies the function `iterator` to each item in `arr`, in parallel.
The `iterator` is called with an item from the list, and a callback for when it
has finished. If the `iterator` passes an error to its `callback`, the main
`callback` (for the `each` function) is immediately called with the error.
Note, that since this function applies `iterator` to each item in parallel,
there is no guarantee that the iterator functions will complete in order.
__Arguments__
* `arr` - An array to iterate over.
* `iterator(item, callback)` - A function to apply to each item in `arr`.
The iterator is passed a `callback(err)` which must be called once it has
completed. If no error has occured, the `callback` should be run without
arguments or with an explicit `null` argument.
* `callback(err)` - A callback which is called when all `iterator` functions
have finished, or an error occurs.
__Examples__
```js
// assuming openFiles is an array of file names and saveFile is a function
// to save the modified contents of that file:
async.each(openFiles, saveFile, function(err){
// if any of the saves produced an error, err would equal that error
});
```
```js
// assuming openFiles is an array of file names
async.each(openFiles, function( file, callback) {
// Perform operation on file here.
console.log('Processing file ' + file);
if( file.length > 32 ) {
console.log('This file name is too long');
callback('File name too long');
} else {
// Do work to process file here
console.log('File processed');
callback();
}
}, function(err){
// if any of the file processing produced an error, err would equal that error
if( err ) {
// One of the iterations produced an error.
// All processing will now stop.
console.log('A file failed to process');
} else {
console.log('All files have been processed successfully');
}
});
```
---------------------------------------
<a name="forEachSeries" />
<a name="eachSeries" />
### eachSeries(arr, iterator, callback)
The same as [`each`](#each), only `iterator` is applied to each item in `arr` in
series. The next `iterator` is only called once the current one has completed.
This means the `iterator` functions will complete in order.
---------------------------------------
<a name="forEachLimit" />
<a name="eachLimit" />
### eachLimit(arr, limit, iterator, callback)
The same as [`each`](#each), only no more than `limit` `iterator`s will be simultaneously
running at any time.
Note that the items in `arr` are not processed in batches, so there is no guarantee that
the first `limit` `iterator` functions will complete before any others are started.
__Arguments__
* `arr` - An array to iterate over.
* `limit` - The maximum number of `iterator`s to run at any time.
* `iterator(item, callback)` - A function to apply to each item in `arr`.
The iterator is passed a `callback(err)` which must be called once it has
completed. If no error has occured, the callback should be run without
arguments or with an explicit `null` argument.
* `callback(err)` - A callback which is called when all `iterator` functions
have finished, or an error occurs.
__Example__
```js
// Assume documents is an array of JSON objects and requestApi is a
// function that interacts
没有合适的资源?快使用搜索试试~ 我知道了~
leanote-windows-ia32-v0.6.zip
共2891个文件
js:1926个
woff:195个
json:152个
5星 · 超过95%的资源 需积分: 9 12 下载量 177 浏览量
2015-06-05
23:41:52
上传
评论
收藏 50.18MB ZIP 举报
温馨提示
leanote-windows-ia32-v0.6.zip 知识管理工具
资源推荐
资源详情
资源评论
收起资源包目录
leanote-windows-ia32-v0.6.zip (2891个子文件)
ctio.3ctype 8KB
atom.asar 122KB
AUTHORS 366B
snapshot_blob.bin 681KB
natives_blob.bin 402KB
benchmark-native.c 613B
CHANGELOG 2KB
CNAME 17B
config.codekit 339KB
config.codekit 60KB
incompat.coffee 230B
83.coffee 228B
text.coffee 213B
jsl.conf 6KB
bootstrap.css 124KB
bootstrap.css 120KB
bootstrap.min.css 100KB
bootstrap.min.css 97KB
default.css 44KB
skin.ie7.min.css 34KB
default.css 33KB
skin.min.css 33KB
font-awesome.css 26KB
skin.min.css 23KB
skin.ie7.min.css 22KB
font-awesome.min.css 21KB
bootstrap-theme.css 19KB
bootstrap-theme.min.css 17KB
index.css 15KB
bootstrap-theme.css 14KB
bootstrap-theme.min.css 13KB
presentation.css 8KB
base.css 7KB
theme.css 6KB
theme.css 6KB
theme.css 6KB
theme.css 6KB
dialog.css 6KB
visualblocks.css 5KB
dialog.css 4KB
style.css 4KB
zTreeStyle.css 3KB
writting.css 3KB
mine.css 2KB
prettify.css 2KB
theme.css 2KB
windows.css 2KB
content.min.css 1KB
content.min.css 1KB
theme.css 1KB
theme.css 1KB
theme.css 1KB
theme.css 1KB
theme.css 1KB
theme.css 1KB
theme.css 1KB
content.inline.min.css 1KB
theme.css 1KB
content.inline.min.css 971B
editor.css 562B
dialog-v4.css 319B
windows.css 305B
icudtl.dat 9.73MB
node.dll 8.32MB
d3dcompiler_47.dll 3.31MB
ffmpegsumo.dll 1.61MB
libGLESv2.dll 1.29MB
msvcr120.dll 948KB
msvcp120.dll 445KB
vccorlib120.dll 242KB
xinput1_3.dll 80KB
libEGL.dll 12KB
strict.dtd 34KB
fontawesome-webfont.eot 55KB
glyphicons-halflings-regular.eot 20KB
tinymce-small.eot 9KB
tinymce.eot 9KB
icomoon-small.eot 8KB
icomoon.eot 8KB
leanote.exe 48.36MB
loading-a-20-black.gif 14KB
icons.gif 12KB
zTreeStandard.gif 5KB
loading-30.gif 5KB
loading-32.gif 5KB
loading-24.gif 4KB
loading-a-24.gif 4KB
loading-a-20-2.gif 4KB
loading-a-20.gif 4KB
loader.gif 3KB
loader.gif 3KB
progress.gif 2KB
spinner.gif 2KB
tabs.gif 1KB
ajax-loader.gif 723B
loading.gif 381B
smiley-cool.gif 354B
smiley-wink.gif 350B
smiley-smile.gif 344B
smiley-laughing.gif 343B
共 2891 条
- 1
- 2
- 3
- 4
- 5
- 6
- 29
资源评论
- daguanju2019-09-28搭建了自己的服务器,很好用。如果能支持在线多人编辑文档就更好了
xigui2011
- 粉丝: 1
- 资源: 2
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功