I'm writing an AJAXy application and when I start doing an ajax call,
I want to block the UI and show a loading graphic until the loading is
done. For various reasons, a number of different functions might
initiate a load and a number might signal its end, and in a particular
sequence two such functions might be called during one "ajax load"
event.
As I was thinking about opimizing JavaScript anyways, I figured I see
if anyone has any thoughts about optimizing the general situation
where you have a "start" function that might be called once its
started and a "stop" function that might be called when nothing is
currently running.
The trivial way to write this would be:
var running=false;
function do_start() {
if (running) return;
running = true;
// Do stuff;
}
function do_stop() {
if(!running) return;
running = false;
// Do stuff;
}
However, the following would also work:
function nullFunct() {};
function startFunct() {
// Do Stuf;
do_stop = stopFunct;
do_start = nullFunct;
}
function stopFunct() {
// Do Stuf;
do_stop = nullFunct;
do_start = startFunct;
}
var do_start = startFunct, do_stop=nullFunct;
Does anyone have any thoughts about taking either approach? I would
suspect that the later approach gets more useful as the test for
"should we allow stuff to happen here" gets ore complicated than I've
shown.
Adam
