Can I run a loop (while, for, dowhile etc) in a callback function. Here is a sample code :
var execute = function (data,callback)
{
//do something with data
callback();
}
execute (data,function(error,returnDataArray)
{
var boo = true;
while(boo)
{
//do something with returnDataArray
if (returnDataArray.length == 10)
boo=false;
}
});
Now, my doubt is, does the main node.js thread wait until the above while loop is executed?
Your main thread will be blocked by the looping occuring inside a callback function. That's because callback functions are just delayed until completion, and then, they're pushed into the JavaScript event loop and executed once the thread is free. In simpler word, everything in node (and JavaScript) happen in a single thread (normal execution, callback, timeouts, etc).
The only way to execute a function into another thread with JavaScript is manually pushing it into another thread. In browser that'll be a web worker, and on node a cluster.
You can have something like this
var execute = function (data,function(error,returnDataArray)
{
//do something with data
var boo = true;
while(boo)
{
//do something with returnDataArray
if (returnDataArray.length == 10)
boo=false;
}
});
or you can use the async module, using function async.parallel
