Nested setTimeout alternative?

Question

I need to execute 3 functions in a 1 sec delay.

for simplicity those functions are :

console.log(\'1\');
console.log(\'2\');
console.log(\'3\');
         


        

Answer 1

I think most simple way to do this is to create some closures within a function.
First i'll recall that you have big interest in using setInterval, since the overhead of the setTimeout might have it trigger 10ms off target. So especially if using short (<50ms) interval, prefer setInterval. So we need to store the function array, the index of latest executed function, and an interval reference to stop the calls.

function chainLaunch(funcArray, time_ms) {
  if (!funcArray || !funcArray.length) return;
  var fi = 0; // function index
  var callFunction = function () {
      funcArray[fi++]();
      if (fi==funcArray.length)
              clearInterval(chainInterval);
   } ;
  var chainInterval = setInterval( callFunction, time_ms);
}

Rq : You might want to copy the function array ( funcArray = funcArray.slice(0); )
Rq2 : You might want to loop within the array
Rq3 : you might want to accept additionnal arguments to chainlaunch. retrieve them with var funcArgs = arguments.slice(3); and use apply on the functions : funcArray[fi++].apply(this,funcArgs);

Anyway the following test works :

var f1 = function() { console.log('1'); };
var f2 = function() { console.log('2'); };
var f3 = function() { console.log('3'); };

var fArr = [f1, f2, f3];

chainLaunch(fArr, 1000);

as you can see in this fiddle : http://jsfiddle.net/F9UJv/1/ (open the console)