javascript - recursive function & setTimeout
I am trying to write a javascript function that when called performs function DoSomething() once, but can be triggered to perform the function repeatedly until triggered to stop.
I am using setTimeout() function. I am not sure if this is best method from performance and memory point of view. Also I would like to avoid global variable if possible
<!DOCTYPE html>
<html>
<script src="jquery.js"></script>
<script>
var globalCheckInventory = false;
$(document).ready(function(){
// start checking inventory
globalCheckInventory = true;
myTimerFunction();
});
// check inventory at regular intervals, until condition is met in DoSomethi开发者_开发百科ng
function myTimerFunction(){
DoSomething();
if (globalCheckInventory == true)
{
setTimeout(myTimerFunction, 5000);
}
}
// when condition is met stop checking inventory
function DoSomething() {
alert("got here 1 ");
var condition = 1;
var state = 2 ;
if (condition == state)
{
globalCheckInventory = false;
}
}
</script>
This is probably the easier way to do what you're describing:
$(function () {
var myChecker = setInterval(function () {
if (breakCondition) {
clearInterval(myChecker);
} else {
doSomething();
}
}, 500);
});
Another way to do it would be the store the timer ID and use setInterval and clearInterval
var timer = setInterval(DoSomething);
function DoSomething() {
if (condition)
clearInterval(timer);
}
I see nothing wrong with your implementation other than the pollution of the global namespace. You can use a closure (self-executing function) to limit the scope of your variables like this:
(function(){
var checkInventory = false, inventoryTimer;
function myTimerFunction() { /* ... */ }
function doSomething() { /* ... */ }
$(document).ready(function(){
checkInventory = true;
/* save handle to timer so you can cancel or reset the timer if necessary */
inventoryTimer = setTimeout(myTimerFunction, 5000);
});
})();
Encapsulate it:
function caller(delegate, persist){
delegate();
if(persist){
var timer = setInterval(delegate, 300);
return {
kill: function(){
clearInterval(timer);
}
}
}
}
var foo = function(){
console.log('foo');
}
var _caller = caller(foo, true);
//to stop: _caller.kill()
加载中,请稍侯......
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