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Javascript polling functions
// The polling function
function poll(fn, callback, timeout, interval) {
var endTime = Number(new Date()) + (timeout || 2000);
interval = interval || 100;
(function p() {
// If the condition is met, we're done!
if (fn()) {
callback();
}
// If the condition isn't met but the timeout hasn't elapsed, go again
else if (Number(new Date()) < endTime) {
setTimeout(p, interval);
}
// Didn't match and too much time, reject!
else {
callback(new Error('timed out for ' + fn + ': ' + arguments));
}
})();
}
// Usage: ensure element is visible
poll(function () {
return document.getElementById('lightbox').offsetWidth > 0;
}, function (err) {
if (err) {
// Error, failure callback
}
else {
// Done, success callback
}
}, 2000, 150);
// The polling function
function poll(fn, timeout, interval) {
var dfd = new Deferred();
var endTime = Number(new Date()) + (timeout || 2000);
interval = interval || 100;
(function p() {
// If the condition is met, we're done!
if (fn()) {
dfd.resolve();
}
// If the condition isn't met but the timeout hasn't elapsed, go again
else if (Number(new Date()) < endTime) {
setTimeout(p, interval);
}
// Didn't match and too much time, reject!
else {
dfd.reject(new Error('timed out for ' + fn + ': ' + arguments));
}
})();
return dfd.promise;
}
// Usage: ensure element is visible
poll(function () {
return document.getElementById('lightbox').offsetWidth > 0;
}, 2000, 150);
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