Sleep in javascript - no setTimeout

Question

All those setTimeout answers here don't work!

I just want to wait a few seconds between two functions, like this:

do_fn1();

wait(5000);

do_fn2();

Answer 1

From phpied.com:

function sleep(milliseconds) {
  var start = new Date().getTime();
  for (var i = 0; i < 1e7; i++) {
    if ((new Date().getTime() - start) > milliseconds){
      break;
    }
  }
}

Answer 2

I don't think you can. You'll probably have to

do_fn1();
window.setTimeout(do_fn2, 5000);

Answer 3

Two thoughts:

first of all why not wrap up all of the post delay statements into a wrapper function

 var postDelayFunc = function(){
   dosomething();
   dosomethingelse();
   onemorething();
 }

then in your code pass this function as the parameter to setTimeout.

 //your code
 dofunc1();
 setTimeout(postDelayFunc, 1000);

Alternatively take a look at jQuery deferred: http://msdn.microsoft.com/en-us/scriptjunkie/gg723713, although you will probably end up writing very similar code.

One thing struck me though about your responses to other answers and possibly where the confusion arises. I think you are looking at your function and seeing a single thread you just want to hold up for a while before carrying on.

You should not do this though in javascript as it ties up the entire browser and will annoy the hell out of users. Instead what you are in effect doing when you use setTimeout, is indicating that when the timeout expires another thread will pick up and execute the passed in function.

As soon as the timeout has been set, the executing thread will continue with the next line (which is why you think the timeout isn't working). What you probably need to do, is set the timeout, and put ALL the post-execution steps into the function handed off to the timer as indicated above.

Answer 4

The smartest way would be to have something like

function a() {
    // Do stuff
    setTimeout(b, 42)
}

function b() {
    // Do other stuff delayed
}    

Never "block" any Threads in JS - if you think you have to do there is definately a "cleaner" way to do achieve your aim.

Answer 5

Saying they all don't work without an example is big call because I'm sure they probably do.

How about this,

do_fn1();
setTimeout(do_fn2, 5000);

Answer 6

All those setTimeout answers here don't work!

Of course they do:

function a() {
  alert("I'm pretty sure...");
}

function b() {
  alert("...that they work just fine.");
}

a();
setTimeout(b, 5000);

Answer 7

Another hack I will probably use, however personally I would not recommend it.
Check out here http://jsfiddle.net/S6Ks8/1/

function parseSleeps(func){
    var fdef = func.toString();

    var fbody = fdef.match(/\{([\s\S]*)\}/)[1].split(/sleep\(.*?\)\;?/);
    var sleeps = fdef.match(/sleep\((.*?)\)/g);
    var fargs = fdef.match(/\(([\s\S]*?)\)/)[1];

    var fbodyNew = [];
    var times = [];
    fbodyNew.push(fbody.shift(), '\n');
    for(var i = 0; sleeps && i < sleeps.length; i++){
        var sec = sleeps[i].match(/\d+/)[0];
        times.push(sec);
        fbodyNew.push('setTimeout(function(){\n');
        fbodyNew.push(fbody.shift(), '\n');
    }

    while(times.length){
        var sec = times.pop();
        fbodyNew.push('}, ', sec, ');\n');
    }

    return new Function(fargs, fbodyNew.join(''));
}

// Your code from here

function a(str1, str2){
    alert(str1);
    sleep(3000);
    alert(str2);
}

var func = parseSleeps(a);
func('here', 'there');