Server : Apache/2.4.41 (Ubuntu) System : Linux absol.cf 5.4.0-198-generic #218-Ubuntu SMP Fri Sep 27 20:18:53 UTC 2024 x86_64 User : www-data ( 33) PHP Version : 7.4.33 Disable Function : pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wifcontinued,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_get_handler,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,pcntl_async_signals,pcntl_unshare, Directory :  /usr/local/lib/node_modules/forever/node_modules/map-stream/

Upload File : current_dir [ Writeable ] document_root [ Writeable ]

# MapStream

Refactored out of [event-stream](https://github.com/dominictarr/event-stream)

##map (asyncFunction[, options])

Create a through stream from an asyncronous function.  

``` js
var map = require('map-stream')

map(function (data, callback) {
  //transform data
  // ...
  callback(null, data)
})

```

Each map MUST call the callback. It may callback with data, with an error or with no arguments, 

  * `callback()` drop this data.  
    this makes the map work like `filter`,  
    note:`callback(null,null)` is not the same, and will emit `null`

  * `callback(null, newData)` turn data into newData
    
  * `callback(error)` emit an error for this item.

>Note: if a callback is not called, `map` will think that it is still being processed,   
>every call must be answered or the stream will not know when to end.  
>
>Also, if the callback is called more than once, every call but the first will be ignored.

##Options 

 * `failures` - `boolean` continue mapping even if error occured. On error `map-stream` will emit `failure` event. (default: `false`)