JS Asynchronous Process Control AVQ (avril.queue)

Source: Internet
Author: User
Tags readfile

Nonsense preface

Write for many years of JS, have encountered the most egg ache thing is callback hell, I believe we also feel empathy.

Many of the industry has put forward a lot of good solutions for this, I understand the main:

    • Pauling event Proxy, easy to understand and simple to get started
    • Lao Zhao's wind.js, writing the most comfortable, most able to express the program sequence of execution logic
    • Promise, personal feeling to solve a hole to introduce another pit, write out the code a big lump, code readability is the worst

I this person idle nothing also love toss, I also build wheels, not for other only for their own code to write comfortable and smooth.

Portal: Currently only supports the node. JS Environment and later has time to increase browser support

    • GitHub Https://github.com/flowforever/avril.queue
    • NPM Install Avril.queue

Brief introduction

Why is called AVQ: the full name is avril.queue because elder brother likes Avril to be named with her name, has nothing to do with the island

Core: AVQ as an asynchronous process control framework with two main elements for asynchronous process control and easy coding

    • Queue execution queues Ensure that program logic executes in sequence
    • The $AwaitData asynchronously waits for the data object, which can be used as a parameter for the next asynchronous request, implementing the core of the coding fluency
Hands Avqbasic Example:q.func, Q. $await, Q. $each
var q = avq ();
var function / * This is not a point to Q, but a new AVQ () object so this is actually a subqueue, and This.error () will throw the error layer on the default and throw no processing on it.    In later chapters I will detail the principle of q.func execution */this. Error (ERR); return res;}) ;   

What to do if fs.readfile needs context

Q. $await, Q. $each, and later q.$ $await, q.$ $each support incoming context as the first parameter, for example

var function  (Err, res) {  this. Error (ERR);  return  res;}); var // the most $awaitData result of Res will be automatically var // by default, the first parameter existed number in the Fs.existe callback (existed) is returned as the value

varAVQ = require (' Avril.queue '));varQ =Avq ();

/*return $AwaitData Object*/var$fileContent = Q. $await (Fs.readfile, ' the/path/of/file.txt ', function(Err, filecontent) { This. Error (ERR); returnfilecontent;});/*convert the $awaitData ' result, return a new $AwaitData object*/var$ids = $fileContent. Convert (function($org) {return$org. Result (). split (' \ n ');}); /*return $AwaitData object which result is list of*/var$users = Q. $each (db. User.findbyid, $ids,function(err, user) { This. Error (ERR); returnuser;}); Q.func (function() {Console.log ($fileContent. Result ()) Console.log ($users. Realresult ());});

Syntax sugar:q.$ $await, q.$ $each, Q. $if ($awaitData, Truefunc), Q. $if ($awaitData, Truefunc). $else (), Q. $if ($awaitData, Truefunc). $elseIf ($otherAwaitData, Othertruefunc)

The general return value for standard node. JS asynchronous Calls is callback (err, result),

var // the difference with $await () is that the last parameter of $await requires Callback:return res;

$fileContent results are automatically used after the asynchronous request is complete.

varAVQ = require (' Avril.queue '));varQ =Avq ();var$fileContent, $ids, $users;/*return $AwaitData Object*/varfilePath1 = ' The/path/of/file1.txt ';varfilePath2 = ' The/path/of/file2.txt ';var$fileExisted =Q. $await (fs.exists, filePath1); q.$if($fileExisted,function() {$fileContent= This. $ $await (fs.readfile, filePath1);}). $Else(function() {$fileContent= This. $ $await (fs.readfile, filePath2);}); Q.func (function() {/*convert the $awaitData ' result, return a new $AwaitData object*/$ids= $fileContent. Convert (function($org) {return$org. Result (). split (' \ n ');   }); /*return $AwaitData object which result is list of*/$users= This. $ $each (db. User.findbyid, $ids); }); Q.func (function() {Console.log ($fileContent. Result ())//only the first level result () is removedConsole.log ($users. Realresult ());//recursive removal of all result ()});


Nobody is perfect, yards no end code, welcome everyone to shoot bricks, if everyone is interested I will continue to launch more API documentation and introduction (everyone is not interested or to continue to write complete, haha).

I think this library is interesting, so let's get a github start.

JS Asynchronous Process Control AVQ (avril.queue)

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.