Accurately run a function when the minute changes?

You can try to be as accurate as you can, setting a timeout each X milliseconds and check if the minute has passed and how much time has passed since the last invocation of the function, but that's about it.

You cannot be 100% sure that your function will trigger exactly after 1 minute, because there might be something blocking the event-loop then.

If it's something vital, I suggest using a cronjob or a separate Node.js process specifically for that (so you can make sure the event loop isn't blocked).

Resources:

http://www.sitepoint.com/creating-accurate-timers-in-javascript/

This may be an idea. The maximum deviation should be 1 second. If you want it to be more precise, lower the milliseconds of setTimeout¹.

setTimeout(checkMinutes,1000);

function checkMinutes(){
  var now = new Date().getMinutes();
  if (now > checkMinutes.prevTime){
    // do something
    console.log('nextminute arrived');
  }
  checkMinutes.prevTime = now;
  setTimeout(checkChange,1000);
}

¹ But, see also this question, about accuracy of timeouts in javascript

First off, you should use setInterval for repeating timers, since it (tries to) guarantee periodic execution, i.e. any potential delays will not stack up as they will with repeated setTimeout calls. This will execute your function every minute:

var ONE_MINUTE = 60 * 1000;

function showTime() {
  console.log(new Date());
}

setInterval(showTime, ONE_MINUTE);

Now, what we need to do is to start this at the exact right time:

function repeatEvery(func, interval) {
    // Check current time and calculate the delay until next interval
    var now = new Date(),
        delay = interval - now % interval;

    function start() {
        // Execute function now...
        func();
        // ... and every interval
        setInterval(func, interval);
    }

    // Delay execution until it's an even interval
    setTimeout(start, delay);
}

repeatEvery(showTime, ONE_MINUTE);