avril.queue

#avril.queue
avril.queue is an async flow control tool, it tries to ease the pain of callback.

It's pretty simple to use. Let's rock.

##install avril.queue

``
npm install avril.queue
`

for now avril.queue only support node env, I would try to make it support the browsers later.

`
/*
assume that we have a file "the/path/of/file.txt"
the file content is :
1
2
3
*/
`



$3



`js
var avQ = require('avril.queue');
var q = avQ();

/ return $AwaitData object /
var $fileContent = q.$await(fs.readFile, 'the/path/of/file.txt'
, function(err, fileContent){
this.error(err);
return fileContent;
});

/ conver the $awaitData' result , return a new $AwaitData object /
var $ids = $fileContent.conver(function($org){
return $org.result().split('\n');
});

/ return $AwaitData object which result is list of /
var $users = q.$each(db.User.findById, $ids, function(err, user){
this.error(err);
return user;
});

q.func(function(){
console.log( $fileContent.result() )
console.log( $users.realResult() );
});
`

###$$await & $$each

`js
var avQ = require('avril.queue');
var q = avQ();

/ return $AwaitData object /
var $fileContent = q.$$await(fs.readFile, 'the/path/of/file.txt');

/ conver the $awaitData' result , return a new $AwaitData object /
var $ids = $fileContent.conver(function($org){
return $org.result().split('\n');
});

/ return $AwaitData object which result is list of /
var $users = q.$$each(db.User.findById, $ids);

q.func(function(){
console.log( $fileContent.result() )
console.log( $users.realResult() );
});
`

###use $await, $each, with context

`js
var avQ = require('avril.queue');
var q = avQ();

/ return $AwaitData object /
var $fileContent = q.$await(fs, fs.readFile, 'the/path/of/file.txt'
, function(err, fileContent){
this.error(err);
return fileContent;
});

/ conver the $awaitData' result , return a new $AwaitData object /
var $ids = $fileContent.conver(function($org){
return $org.result().split('\n');
});

/ return $AwaitData object which result is list of /
var $users = q.$each(db.User, db.User.findById, $ids, function(err, user){
this.error(err);

/* use this.$$await instead of q.$$await
* use this.$$wait, the queue will wait the asynCall ready then go to next step
* use q.$$wait only append current asynCall to the end of the queue, it's not what we want
*/
user.blogs = this.$$await(db.Blogs, db.Blogs.findByUserId, user.id);

return user;
});

q.func(function(){
console.log( $fileContent.result() )
console.log( $users.realResult() );
});
`

###use q.$if($awaitData, trueFunc).$else(falseFunc)

`js
var avQ = require('avril.queue');
var q = avQ();
var filePath = 'the/path/of/file.txt';
var $fileExisted = q.$await(fs.exists, filePath);
var $fileContent;
q.$if($fileExited, function(){
/* use this.$$await instead of q.$$await
* use this.$$wait, the queue will wait the asynCall ready then go to next step
* use q.$$wait only append current asynCall to the end of the queue, it's not what we want
*/
$fileContent = this.$$await(fs.readFile, filePath);
})
q.func(function(){
if($fileContent){
console.log($fileContent.result());
}
});

var otherPath = 'the/path/of/otherFile.txt';

q.$if($fileContent, function(){
$fileContent = this.$$await(fs.readFile, filePath);
}).$elseIf(q.$await(fs.exits, otherPath), function() {
$fileContent = this.$$await(fs.readFile, otherPath);
});

q.func(function(){
if($fileContent){
console.log($fileContent.result());
}
})

``