[英]setTimeout fires immediately if the delay more than 2147483648 milliseconds
如果delay
超过2147483648毫秒(24.8551天),该功能将立即触发。
setTimeout(function(){ console.log('hey') }, 2147483648) // this fires early
setTimeout(function(){ console.log('hey') }, 2147483647) // this works properly
我在Chrome v26和Node.js v8.21下尝试过它
setTimeout的上限是0x7FFFFFFF
(或十进制的2147483647
)
这是因为setTimeout使用32位整数来存储其延迟值,因此高于此值的任何内容都会导致问题
如果你想要在X天数之后触发的超时,你可以尝试使用setInterval
而不是像这样的较低延迟值
function setDaysTimeout(callback,days) {
// 86400 seconds in a day
var msInDay = 86400*1000;
var dayCount = 0;
var timer = setInterval(function() {
dayCount++; // a day has passed
if(dayCount == days) {
clearInterval(timer);
callback.apply(this,[]);
}
},msInDay);
}
然后你会像这样使用它
setDaysTimeout(function() {
console.log('Four days gone');
},4); // fire after 4 days
由于您被限制为32位,只需将setTimeout包装在递归函数中,如下所示:
function setLongTimeout(callback, timeout_ms)
{
//if we have to wait more than max time, need to recursively call this function again
if(timeout_ms > 2147483647)
{ //now wait until the max wait time passes then call this function again with
//requested wait - max wait we just did, make sure and pass callback
setTimeout(function(){ setLongTimeout(callback, (timeout_ms - 2147483647)); },
2147483647);
}
else //if we are asking to wait less than max, finally just do regular setTimeout and call callback
{ setTimeout(callback, timeout_ms); }
}
这不是太复杂,应该可扩展到javascript编号的限制,即1.7976931348623157E + 10308,按这个毫秒数,我们都将死亡并消失。
为了使你能够设置setLongTimeout,你可以修改函数来接受一个通过引用传递的对象,从而将范围保留回调用函数:
function setLongTimeout(callback, timeout_ms, timeoutHandleObject)
{
//if we have to wait more than max time, need to recursively call this function again
if(timeout_ms > 2147483647)
{ //now wait until the max wait time passes then call this function again with
//requested wait - max wait we just did, make sure and pass callback
timeoutHandleObject.timeoutHandle = setTimeout(function(){ setLongTimeout(callback, (timeout_ms - 2147483647), timeoutHandleObject); },
2147483647);
}
else //if we are asking to wait less than max, finally just do regular setTimeout and call callback
{ timeoutHandleObject.timeoutHandle = setTimeout(callback, timeout_ms); }
}
现在您可以调用超时,然后在需要时取消它:
var timeoutHandleObject = {};
setLongTimeout(function(){ console.log("Made it!");}, 2147483649, timeoutHandleObject);
setTimeout(function(){ clearTimeout(timeoutHandleObject.timeoutHandle); }, 5000);
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