Javascript时间:如何每5、7和8秒执行一次函数? [英] Javascript Timing: How do I execute a function every 5, 7, and 8 seconds?

问题描述

假设我有一个函数log()

var log = function(i) {
    console.log('Executing at time: ' + i);
}

我想每x，y和z秒间隔执行一次log()吗?

And I want to execute log() on an interval, every x, y, and z seconds?

让我们将x，y和z分别设置为5、7和8.

Let's arbitrarily set x, y, and z to 5, 7, and 8.

var x = 5;
var y = 7;
var z = 8;

我想每隔x，y和z秒调用一次log():

And every x, y, and z seconds I want to call log():

// Every 5 seconds:
log(x);
// Every 7 seconds:
log(y);
// Every 8 seconds:
log(z);

我可以尝试使用三个setTimeout()来单独运行这些功能.但是，等一下，javascript不是异步的，因此执行一个setTimeout()将会阻止执行另外两个...嗯...

I could use try using three setTimeout()s to run these functions alone. But wait, javascript isn't asynchronous, so the execution of one setTimeout() will prevent the execution the other two... Hmm...

我可以计算时间差，以使第一个setTimeout()引起的延迟不会破坏第二个和第三个的时间:

I could calculate the difference in the times, so that the delay caused by the first setTimeout() won't break the timing of the second and third:

// x is at 5 seconds, run 5000 milliseconds after the start
setTimeout(function() {  log(x); }, 5000);
// y is at 7 seconds after start, or 2000 milliseconds after x is done
setTimeout(function() {  log(y); }, 2000);
// z is at 7 seconds after start, or 1000 milliseconds after y is done
setTimeout(function() {  log(z); }, 1000);

但是时间永远不会完全正确，因为我的log()函数的执行将至少花费少量时间.另外，当我尝试在其中添加更多log()命令时，或者当我尝试按设定的时间间隔重复整个过程时，这会变得很混乱.

But the timing would never be exactly right, as the execution of my log() function will take at least a small amount of time. Also, this get's messy when I try and add more log() commands in, or when I try and repeat the entire process at a set interval.

我可以使用循环，计算秒数，并在x，y和zth秒执行命令:

I could use a loop, count the seconds, and on the x, y, and zth second, execute my commands:

var i = 0;
while(i<10) {
    // wait 1 second (pointless function, don't know a better way to wait a second)
    setTimeout(function() { console.log(' ... '); }, 1000);
    i++;

    // execute x, y, or z depending on what time it is
    switch(i) {
        case 4: 
            log(x);
        case 6: 
            log(y);
        case 7: 
            log(z);
    }
}

但是这种计数"方法(我在其中使用setTimeout()执行无用的命令)实际上使我感到效率低下.

But this method of 'counting', where I execute a useless command using setTimeout(), really just bothers me as inefficient.

是否有更好的方法来测量javascript中的时间，并让函数在将来的特定时间执行?对我来说，关键是它不只是每5秒运行一次log()"，因为我理解这一点.是在时间x，y和z时运行log()"使我感到困惑.

Is there a better way to measure time in javascript, and have a function execute at certain times in the future? The key for me is that it's not just "run log() every 5 seconds", because I understand that. It's "run log() at times x, y and z" that confuses me.

推荐答案

您可以使用函数"setInterval".这是一个示例:

You can use the function "setInterval". Here is a example:

var interval1Id = setInterval(function(){
    console.log("logging every 5 seconds");
},5000);

var interval2Id = setInterval(function(){
    console.log("logging every 7 seconds");
},7000);

var interval3Id = setInterval(function(){
   console.log("logging every 8 seconds");
},8000);

变量"intervalXId"被保存，以防万一您要停止任何间隔.

Variables "intervalXId" are saved just in case you want to stop any interval.

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