Calling a function every 60 seconds

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情书的邮戳
情书的邮戳 2020-11-22 08:24

Using setTimeout() it is possible to launch a function at a specified time:

setTimeout(function, 60000);

But what if I would l

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13条回答
  • 2020-11-22 09:02

    If you don't care if the code within the timer may take longer than your interval, use setInterval():

    setInterval(function, delay)
    

    That fires the function passed in as first parameter over and over.

    A better approach is, to use setTimeout along with a self-executing anonymous function:

    (function(){
        // do some stuff
        setTimeout(arguments.callee, 60000);
    })();
    

    that guarantees, that the next call is not made before your code was executed. I used arguments.callee in this example as function reference. It's a better way to give the function a name and call that within setTimeout because arguments.callee is deprecated in ecmascript 5.

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  • 2020-11-22 09:02
    setInterval(fn,time)
    

    is the method you're after.

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  • 2020-11-22 09:04

    A better use of jAndy's answer to implement a polling function that polls every interval seconds, and ends after timeout seconds.

    function pollFunc(fn, timeout, interval) {
        var startTime = (new Date()).getTime();
        interval = interval || 1000;
    
        (function p() {
            fn();
            if (((new Date).getTime() - startTime ) <= timeout)  {
                setTimeout(p, interval);
            }
        })();
    }
    
    pollFunc(sendHeartBeat, 60000, 1000);
    

    UPDATE

    As per the comment, updating it for the ability of the passed function to stop the polling:

    function pollFunc(fn, timeout, interval) {
        var startTime = (new Date()).getTime();
        interval = interval || 1000,
        canPoll = true;
    
        (function p() {
            canPoll = ((new Date).getTime() - startTime ) <= timeout;
            if (!fn() && canPoll)  { // ensures the function exucutes
                setTimeout(p, interval);
            }
        })();
    }
    
    pollFunc(sendHeartBeat, 60000, 1000);
    
    function sendHeartBeat(params) {
        ...
        ...
        if (receivedData) {
            // no need to execute further
            return true; // or false, change the IIFE inside condition accordingly.
        }
    }
    
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  • 2020-11-22 09:07

    Call a Javascript function every 2 second continuously for 10 second.

    var intervalPromise;
    $scope.startTimer = function(fn, delay, timeoutTime) {
        intervalPromise = $interval(function() {
            fn();
            var currentTime = new Date().getTime() - $scope.startTime;
            if (currentTime > timeoutTime){
                $interval.cancel(intervalPromise);
              }                  
        }, delay);
    };
    
    $scope.startTimer(hello, 2000, 10000);
    
    hello(){
      console.log("hello");
    }

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  • 2020-11-22 09:12

    A good example where to subscribe a setInterval(), and use a clearInterval() to stop the forever loop:

    function myTimer() {
    
    }
    
    var timer = setInterval(myTimer, 5000);
    

    call this line to stop the loop:

    clearInterval(timer);
    
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  • 2020-11-22 09:14
    // example:
    // checkEach(1000, () => {
    //   if(!canIDoWorkNow()) {
    //     return true // try again after 1 second
    //   }
    //
    //   doWork()
    // })
    export function checkEach(milliseconds, fn) {
      const timer = setInterval(
        () => {
          try {
            const retry = fn()
    
            if (retry !== true) {
              clearInterval(timer)
            }
          } catch (e) {
            clearInterval(timer)
    
            throw e
          }
        },
        milliseconds
      )
    }
    
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