Shared data problem

Question

I have a code like this:

var increment = 200;

for (var j=0; j<10; j++){

  var print = function(){ console.log("===== J ===== "+j); }

  setTimeout(print, increment); 

  increment+= 200;

}

Console always print 10. I think that could be for statement and setTimeout are executed in different threads. How i can do to print the correct value of j?

Thanks in advance.

Can you clarify your question? I don't see anything in your code that would print only "10" and there is no variable `i`. — George Cummins, Jun 23 '11 at 17:26

score 1 · Accepted Answer · edited May 23 '17 at 10:28

1

This is a standard binding issue, you can find a lot of similar questions on stackoverflow.

Basically, it is using one 'j' for all values. Try this instead:

function getBoundLog(j)
{
   return function(){console.log("===== J ===== "+j);}
}
var increment = 200;

for (var j=0; j<10; j++){

  setTimeout(getBoundLog(j), increment); 

  increment+= 200;

}

edited May 23 '17 at 10:28

Community

1
1

answered Jun 23 '11 at 17:25

cwallenpoole

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score 1 · Answer 2 · answered Jun 23 '11 at 17:27

You have scope problem I think. You are basically over writing the print function 10 times and because you wait to call the function with setTimeout by the time it gets called the function is actually

var print = function(){ console.log("===== J ===== "+10); }

Shared data problem

2 Answers2