setTimeout in Node.js loop
setTimeout is non blocking, it is asynchronous. You give it a callback and when the delay is over, your callback is called.
Here are some implementations:
Using recursion
You can use a recursive call in the setTimeout
callback.
function waitAndDo(times) {
if(times < 1) {
return;
}
setTimeout(function() {
// Do something here
console.log('Doing a request');
waitAndDo(times-1);
}, 1000);
}
Here is how to use your function:
waitAndDo(2000); // Do it 2000 times
About stack overflow errors: setTimeout
clear the call stack (see this question) so you don't have to worry about stack overflow on setTimeout
recursive calls.
Using generators (io.js, ES6)
If you are already using io.js (the "next" Node.js that uses ES6) you can solve your problem without recursion with an elegant solution:
function* waitAndDo(times) {
for(var i=0; i<times; i++) {
// Sleep
yield function(callback) {
setTimeout(callback, 1000);
}
// Do something here
console.log('Doing a request');
}
}
Here is how to use your function (with co):
var co = require('co');
co(function* () {
yield waitAndDo(10);
});
BTW: This is really using a loop ;)
Generator functions documentation.
You need something like this
var counter = 5;
function makeRequst(options, i) {
// do your request here
}
function myFunction() {
alert(counter);
// create options object here
//var options = {
// host:'www.host.com',
// path:'/path/'+counter
//};
//makeRequest(options, counter);
counter--;
if (counter > 0) {
setTimeout(myFunction, 1000);
}
}
See also this fiddle
At the point of the alert(count);
you can do your call to the server.
Note that the counter works opposite (counting down). I updated with some
comments where to do your thing.