Need some concept of threading in java script?

Question

I need some concept of threading java script.Actually I struck in one problem .Problem is that I have one function A () calling function B and C.

function A(){
   B();
   C();
}

function B(){
   //doing some task 
   i=something;
   alert(i);
}

function C(){
   // i need value I here.
   alert(i)    //getting undefined 
}

I need to synchronised call ...

All those calls are synchronized. In other words, the call to `B()` will be called and completed, before the call to `C()`. So I'm not sure why you're talking about [Threading](http://en.wikipedia.org/wiki/Thread_(computing)), when it looks like you're talking about [Scope](http://en.wikipedia.org/wiki/Scope_(computer_science)). — Erik Philips, Jul 17 '13 at 05:04
please check this question http://stackoverflow.com/questions/17689556/how-to-synchronise-call-in-jquery-or-javascript — user2563256, Jul 17 '13 at 05:12

mplungjan · Accepted Answer · 2013-07-17T05:21:37.027

5

How about

function A(){
   C(B());
}

function B(){
   //doing some task 
   var i=something;
   return i;
}

function C(i){
   // i need value I here.
   alert(i)    
}

or split out for readability

function A(){
   var resultFromB = B(); //
   C(resultFromB);
}

function B(){
   //doing some task 
   var result=something;
   return result; // return it to calling function
}

function C(resultOriginallyFromB) { // passing it
   alert(resultOriginallyFromB);    
}

edited Jul 17 '13 at 05:21

answered Jul 17 '13 at 04:55

mplungjan

169,008
28
173
236

5

**+1** for avoiding globals. – michaelb958--GoFundMonica Jul 17 '13 at 04:56
1

not quite clear that `B()` is returning something to be passed along later, but it does save on memory by not re-declaring a variable. – Brombomb Jul 17 '13 at 04:58
@Brombomb you mean I should have `var returnedFromB=B();` in C? – mplungjan Jul 17 '13 at 05:01
1

@mplungjan I think it would help with readability, and be a simpler form of code. This may help the author fully grasp what you are doing so it can be applied later and not fall into some kind of nesting hell. – Brombomb Jul 17 '13 at 05:03

score 1 · Answer 2 · edited May 23 '17 at 12:21

1

Set i as global like,

var i=null;// global i
function A(){
   B();
   C();
}

function B(){
   //doing some task 
   i=something;
   alert(i);
}

function C(){
   i need value I here.
   alert(i)    //getting undefined 
}

Read this also

Alternatively, you can use return in B() like,

function A(){
   i=B();
   C(i);//passing i in C()
}

function B(){
   //doing some task 
   i=something;
   alert(i);
   return i;//return i
}

function C(i){
   // value i has been passed in.
   alert(i);
}

edited May 23 '17 at 12:21

Community

1
1

answered Jul 17 '13 at 04:51

Rohan Kumar

40,431
11
76
106

I'll give you the benefit of the doubt – mplungjan Jul 17 '13 at 05:02
Ok, I also removed the comment. – Rohan Kumar Jul 17 '13 at 05:02

loxxy · Answer 3 · 2013-07-17T05:12:10.267

0

Actually it should not really be alerting undefined in function C. As i would have become globally defined already, without the use of var.

Besides try doing it this way, so that you don't clutter the global space:

(function() {

  var i;

  function A(){
   B();
   C();
  }

  function B(){
     //doing some task 
     i=4;       // --- or something
     alert(i);  // --- will alert 4
  }

  function C(){
     // i need value I here.
     alert(i)    // --- will alert 4
  }

  A();  // --- Assuming you were calling 'A' earlier as well

})();

And yes, nothing related to threading here.

edited Jul 17 '13 at 05:12

answered Jul 17 '13 at 05:04

loxxy

12,990
2
25
56

what about this http://stackoverflow.com/questions/17689556/how-to-synchronise-call-in-jquery-or-javascript – user2563256 Jul 17 '13 at 05:11
Have a look there, now. – loxxy Jul 17 '13 at 05:17
please check again this question .http://stackoverflow.com/questions/17689556/how-to-synchronise-call-in-jquery-or-javascript – user2563256 Jul 17 '13 at 05:35

Need some concept of threading in java script?

3 Answers3