I didn't get library async for node.js, where i'm wrong?

Question

I didn't get library async for node.js, where i'm wrong?

I tried a lot to use aync library in nodejs but my simpliest test even don't works.

var async = require('async');

var i = 0 ;

var inc = function(){
    i++;
} ;

var show = function(){
    console.log(i) ;
} ;

var err = function(err){
    console.log(err) ;
} ;

async.forever(inc,err) ;
async.forever(show,err) ;

Function don't loop at all and the output is only

What i'm doint wrong please.

node.js
asynchronous

Answer 1

async.forever() passes a callback to show and inc that they need to call:

var inc = function(done){
    i++;
    setImmediate(done);
};

var show = function (done) {
    console.log(i);
    setImmediate(done);
};

Using setImmediate (or setTimeout) makes the call asynchronous so you don't get a stack overflow error:

var inc = function(done){
    i++;
    done();
};

RangeError: Maximum call stack size exceeded

var inc = function(done){
                  ^

And, keep in mind that the async library doesn't make tasks asynchronous; it assumes the tasks are already asynchronous and simply helps manage them. Using synchronous tasks with async will still block in most cases.