resting_nonblocking_for_loop.js

//suppose you want to insert 15000000 rows to database
// i can tell you the future your program will crush
// because of background processes will be full to to the limits of the buffers for I/O
// so to not crush the system you have to let go everynow and then
//
//for(var i=0;i<a.length;i++) 
//{
//}
function forloop(from_i,to_i,fn,done,max_continious_loops_i)
{
 var i=from_i;
 if(!max_continious_loops_i)max_continious_loops_i=3000;
 function loop()
 {
  for(;i<to_i&&max_continious_loops_i>=0;i++,max_continious_loops_i--)
   fn(i);
  if(i<to_i) setTimeout(loop,150)// let rest every loop for 100ms to do other events processing
  else if(done)done();
 }
 setTimeout(loop,50)// let return immediately
}
//example1:
//forloop(0,30,function(i){console.log(new Date().getTime(),i)},function(){console.log('done')},10)
//example2:
// var arr=[1,2,3]
// forloop(0,arr.length,function(i)
// {
//  console.log(new Date().getTime(),arr[i])
// },function()
// {
//  console.log('done')
// })



//for(var i=0;i<a.length;i++) 
//{
//}
function asyncforloop(from_i,to_i,fn,done,max_continious_loops)
{
 var i=from_i;
 if(!max_continious_loops)max_continious_loops=max_continious_loops;
 var max_continious_loops_i=max_continious_loops
 function loop()
 {
  function next_end()
  {
   max_continious_loops_i=max_continious_loops;
   if(i<to_i) setTimeout(loop,150)// let rest every loop for 100ms to do other events processing
   else if(done)done();
  }
  
  var maxdeepi=0;
  function next()
  {
   i++;max_continious_loops_i--;
   if(maxdeepi++>2000){maxdeepi=0;setTimeout(run,0);}
   else run();
  }
  function run()
  {
   if(i<to_i&&max_continious_loops_i>0)
    fn(i,next);
   else
    next_end()
  }
  run()
 }
 setTimeout(loop,50)// let return immediately
}
//example1:
//forloop(0,30,function(i,cb){console.log(new Date().getTime(),i);cb();},function(){console.log('done')},10)
//example2:
// var arr=[1,2,3]
// forloop(0,arr.length,function(i,cb)
// {
//  console.log(new Date().getTime(),arr[i])
//  cb();
// },function()
// {
//  console.log('done')
// })