Does Javascript Settimeout Stop Other Script Execution
Solution 1:
No, setTimeout does not wait for you (hence, JS has no pause function). What setTimeout does is set aside that task at a later time, and allow the next line to be executed. when that timeout is reached , it inserts that task into the execution line. and when no other code is running, it executes the function that was indicated.
what you want to do is give a callback to your fillTree() and execute when it's done.
function fillTree(callback){
//do something very longcallback(); //execute passed function when it's done
}
fillTree(function(){
checkSelectedBoxes(); //executes only when fillTree finishes
})
Solution 2:
its a CMS i am using and the tree is set in some other js file which I am not to interfere with as it is used many other functions and the cases may not be always same
If the fillTree() function cannot be modified you can wrap it in your own function and apply a callback function to that. Try this:
function doStuff(callback) {
fillTree();
// Call the callback parameter (checkSelectedBoxes() in this case)// when fillTree() has completedcallback();
}
doStuff(checkSelectedBoxes);
Solution 3:
The setTimeout function does not wait execution and you can clearly check it in the following snippet. You can see how, given the array waitTimes of random times, the Array.map function will print out first all the time[index]=waitTimes[index] values, then the wait[index]=waitTimes[index] when the setTimeout is fired exactly after waitTimes[index] milliseconds.
varconsole = {
log: function(s) {
document.getElementById("console").innerHTML += s + "<br/>"
}
}
var roundDecimals = function(num, pos) {
pos = pos || 4;
return (Math.round(num * Math.pow(10, pos)) / Math.pow(10, pos));
}
var arrayRangeMap = function(a, block) {
c = [];
while (a--) c[a] = block();
return c
};
var getRandomArbitrary = function(min, max) {
return (Math.random() * (max - min) + min);
}
// random 10 wait times, 3 decimal positionsvar waitTimes = arrayRangeMap(10, function() {
returnroundDecimals(getRandomArbitrary(0.250, 0.5, 3) * 1000, 2);
});
waitTimes.map(function(item, index) {
setTimeout(function() {
console.log("wait[" + index + "]=" + item);
}, item);
console.log("time[" + index + "]=" + item);
});<divid="console" />Solution 4:
I just made a test which may be of interest:
<!DOCTYPE html><html><head><script>/* test: if returns in around 1000ms, must interrupt, otherwise it is indeed
not going to let timeout work until work is done. */window.onload = function() {
var before = performance.now();
setTimeout(function() {
alert('completed in ~' + (performance.now() - before) + ' nanoseconds.');
}, 1000);
/* count to 2^31 - 1... takes 8 seconds on my computer */for (var i = 0; i < 0xffffffff; ++i) {
/* me busy, leave me alone */
}
};
</script></head><body></body></html>I'm now really curious how JavaScript knows when certain amount of time has elapsed. Does it spawn a thread that sleeps for a period of time? And if so is there a limit on how many threads sleep, or are sleeping threads "stored" until they are needed? Much confuse.
I think it has something to do with
"If it doesn't need to be exactly 1s, then just usleep a second. usleep and sleep put the current thread into an efficient wait state that is at least the amount of time you requested (and then it becomes eligible for being scheduled again).
If you aren't trying to get near exact time there's no need to check clock()."
--pthread sleep function, cpu consumption
So I guess the operating system does the scheduling for you, at which point it interrupts the engine, and the engine stops the world and puts the timeout function on top of the queue to be executed as soon as possible?
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