TameJS - tame asynchronous programming

What is TameJS?

TameJS is a Javascript extension that makes event / asynchronous programming more simple and elegant. It is very easy to use with nodejs or other v8 projects.

Simple example

Suppose we have a dating site, and we want to write a handler for the user “Angel” to visit the user’s page “Buffy”.

The algorithm of such a visit is as follows:

• calculate a rating (score), as far as Buffy is suitable for Angel (common interests and preferences)
• find the next pair for angel
• note visit, record time of visit
• send Buffy a notice of visit only if - 1) the similarity rating is high and 2) users have not visited each other’s pages

With linear programming, the code would look like this:

handleVisit : function(angel, buffy) { var match_score = getScore(angel, buffy); var next_match = getNextMatch(angel); var visit_info = recordVisitAndGetInfo(angel, buffy); if (match_score > 0.9 && ! visit_info.last_visit) { sendVisitorEmail(angel, buffy); } doSomeFinalThings(match_score, next_match, visit_info); } 

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It looks clear, but we need to use asynchronous programming, and the code becomes like this:

 handleVisit : function(angel, buffy) { getScore(angel, buffy, function(match_score) { getNextMatch(angel, function(next_match) { recordVisitAndGetInfo(angel, buffy, function(visit_info) { if (match_score > 0.9 && ! visit_info.last_visit) { sendVisitorEmail(angel, buffy); } doSomeFinalThings(match_score, next_match, visit_info); }); }); }); } 

Now the code is correct, asynchronous, does not contain blocking calls, but reading it has become noticeably more difficult for, for example, a third-party programmer.
Also, we can see that in our code, calls to the functions getScore, getNextMatch and recordVisitAndGetInfo are independent of each other and could be executed in parallel.
What will help us TameJS?

C TameJS code will look like this:

 handleVisit : function(angel, buffy) { await { getScore (angel, buffy, defer(var score)); getNextMatch (angel, buffy, defer(var next)); recordVisitAndGetInfo (angel, buffy, defer(var vinfo)); } if (score > 0.9 && ! vinfo.last_visit) { sendVisitorEmail(angel, buffy); } doSomeFinalThings(score, next, vinfo); } 

The code became clear, readable, and at the same time it is completely asynchronous and runs faster than the previous asynchronous version due to the parallel execution of getScore, getNextMatch and recordVisitAndGetInfo!

Did you like as well as me?

Install TameJS

Installation in Node.JS is done via the npm package manager:

 npm install -g tamejs 

And further in the code we register the language extension:

 require ('tamejs').register (); // register the *.tjs suffix require ("mylib.tjs"); // then use node.js's import as normal 

That's all! Further, Tame itself compiles tjs files into native JS.

How TameJS works

TameJS syntax sugar is enclosed in just two, shared keywords await and defer

 var res1, res2; await { doOneThing(defer(res1)); andAnother(defer(res2)); } thenDoSomethingWith(res1, res2); 

The await block marks a section of code that contains external events, for example, communication with a network or work with a disk, or a timer. The await block contains multiple defers. Passing an await block is completed only after all the defers in the block have been executed. defer () returns an anonymous function that should be used as a callback for asynchronous calls. If your callback functions assume arguments, specify this set of arguments in defer (). These results will be available after the await block is completed.

About the authors

TameJS is developed by OkCupid and is distributed under the MIT license. There is a repository in github , the project is young, there is activity in the project.
Project site - tamejs.org

Alternatives

If you are interested in extensions that affect the flow of commands, it is recommended to pay attention also to StratifiedJS , Step and Seq .