Update progressbar in each loop - javascript

I have a progress bar that I update in a loop of many iterations.
https://jsfiddle.net/k29qy0do/32/
(open the console before you click the start button)
var progressbar = {};
$(function () {
progressbar = {
/** initial progress */
progress: 0,
/** maximum width of progressbar */
progress_max: 0,
/** The inner element of the progressbar (filled box). */
$progress_bar: $('#progressbar'),
/** Set the progressbar */
set: function (num) {
if (this.progress_max && num) {
this.progress = num / this.progress_max * 100;
console.log('percent: ' + this.progress + '% - ' + num + '/' + this.progress_max);
this.$progress_bar.width(String(this.progress) + '%');
}
},
fn_wrap: function (num) {
setTimeout(function() {
this.set(num);
}, 0);
}
};
});
$('#start_button').on('click', function () {
var iterations = 1000000000;
progressbar.progress_max = iterations;
var loop = function () {
for (var i = 1; i <= iterations; i++) {
if (iterations % i === 100) {
progressbar.set(i); //only updates the progressbar in the last iteration
//progressbar.fn_wrap(i); //even worse, since no output to the console is produced
}
}
}
//setTimeout(loop, 0);
loop();
});
The console is updated iteratively as expected.
However, the progressbar is not updating.
The problem is that the browser window seems to 'hang' until the loop finishes.
Only the console is updated, not the progressbar.
I have tried to add the setTimeout, as suggested below, in several places.
But that just makes things worse, because I then do not even get the console to output the progress while executing the loop.

Okay, I found a solution in the answer to this question:
Javascript: How to update a progress bar in a 'for' loop
var i = 0;
(function loop() {
i++;
if (iterations % i === 100) {
progressbar.set(i); //updates the progressbar, even in loop
}
if (i < iterations) {
setTimeout(loop, 0);
}
})();
My solution:
https://jsfiddle.net/ccvs4rer/3/

Lets break this down to steps
Step 1: Clean up HTML
Assuming the purpose of your question is to understand how to work the progress bar and not the styles or the labels (loading, please be patient, etc.). Lets just have the progress bar and the start button.
<div id='progressbar-outer' style="">
<div id='progressbar' style=""></div>
</div>
<button id="start_button">Start</button>
Step 2: The Styles
Lets make the progress bar visible to the user
#progressbar-outer {
height:2em;
border:5px solid #000;
width:15em;
}
#progressbar {
width:0%;
background-color:#F00;
height:100%;
}
Step 3: Using setTimeout where it belongs
In your code, you have used setTimeout to set the value of your progress bar. However, the for loop is still active.
for (var i = 1; i <= iterations; i++) {
if (iterations % i === 100) {
progressbar.set(i); //only updates the progressbar in the last iteration
//progressbar.fn_wrap(i); //even worse, since no output to the console is produced
//setTimeout(function() {
// progressbar.set(i);
//}, 0);
}
}
The use of setTimeout does not affect the rest of the code. Hence, the UI was held hostage till the loop ended. Try the following code.
$('#start_button').on('click', function () {
var iterations = 100;
progressbar.progress_max = iterations;
var loop = function (value) {
progressbar.set(value);
if (value < iterations) setTimeout(function () {
loop(value + 1)
}, 30);
else $('#progressbar').css('background-color', '#0F0');
}
loop(1);
});
Preview
Try this fiddle: https://jsfiddle.net/Ljc3b6rn/4/

What you really want is an Asynchronous loop to allow the browser to update the DOM in between iterations.
JSFiddle: http://jsfiddle.net/u5b6gr1w/
function delayedLoop(collection, delay, callback, context) {
context = context || null;
var i = 0,
nextInteration = function() {
if (i === collection.length) {
return;
}
callback.call(context, collection[i], i);
i++;
setTimeout(nextInteration, delay);
};
nextInteration();
}
Some HTML:
<div class="progress-bar"><div style="width: 0"></div></div>
A splash of CSS:
.progress-bar {
border: 1px solid black;
background-color: #f0f0f0;
}
.progress-bar div {
background-color: red;
height: 1.25em;
}
And some JavaScript to wire things together:
var progressBar = document.querySelector(".progress-bar div"),
items = [1,2,3,4,5,6,7,8,9,10];
delayedLoop(items, 500, function(item, index) {
var width = (item / items.length * 100) + "%";
progressBar.style.width = width;
progressBar.innerHTML = width;
});

My guess would be that all your progress updates are running in the same call stack. While JavaScript code is running, the DOM cannot update. Maybe this question will help you come up with a work-around.

What do you wnat to do? Why do you need it? You should only use a progressbar when you have to wait for something to finish. But we don't know what you do on your page.
If you want to display the progress of an ajax upload:
$.ajax({
...
xhr: function() {
var xhr = $.ajaxSettings.xhr();
$(xhr.upload).bind("progress", function(event) {
var e = event.originalEvent;
var percent = 0;
if (e.lengthComputable)
percent = Math.ceil(e.loaded/e.total*100);
$("#progress").width(percent+"%");
});
return xhr;
}
...
});
For images, you need an ajax call:
$.ajax({
method: "GET",
url: "http://example.com/path/image.jpg",
xhr: function() {/* see the code above*/ }
...
});
For getting the content of an uploaded file:
var reader = new FileReader();
reader.readAsText(uploadedFile);
$(reader).bind("progress", function(e) {
var percent = 0;
if (e.lengthComputable)
percent = Math.ceil(e.loaded/e.total*100);
$("#progress").css("width", percent+"%");
});
For large around of process, like math or appending a lot of divs that will take 10+ secons:
Main.js:
var worker = new Worker("Worker.js");
$(worker).bind("message", function(data) {
$("#progress").width((data*100)+"%");
});
Worker.js:
var total = 43483,
finished = 0,
doStuff = function() {
++finished;
return 1+1;
};
setInterval(function()
{
self.postMessage(finished/total);
}, 100);
for (var i = 0; i < total; ++i)
setTimeout(doStuff, i*10);
Because it's nice, and you want to tell the user there's a progress when there isn't, just animate the div:
$("#progress").animate({width: "100%"}, 3000);

You can use promises to wait until the width is set before continuing the loop.
Updating the progress bar for 1000000000 iterations will be slow if you go 1 by 1, so you might find it useful to decrease the update frequency.
Instead of a for loop, I used a recursive function that loops when the promise has been fulfilled.
set: function (num) {
var deferred = $.Deferred();
if (this.progress_max && num) {
this.progress = num / this.progress_max * 100;
var self = this;
self.$progress_bar.animate({"width": String(this.progress) + '%'}, "fast", function() {
deferred.resolve();
});
return deferred;
}
}
$('#start_button').on('click', function () {
var iterations = 1000000000;
var i = 0;
progressbar.progress_max = iterations;
var loop = function(){
i+=100000000;
if(i <= iterations){
progressbar.set(i).then(function(){
loop();
}); ;
}
};
loop();
});
https://jsfiddle.net/k29qy0do/34/

You have to use window.requestAnimationFrame, otherwise the browser will block until your loop is finished. The callback passed to requestAnimationFrame will get a timestamp as a parameter which you might be able to use for calculations of the progress.

This are my 2 takes on the question:
Using a web worker. The webworker blob code comes from here
Web worker code:
<script type="text/ww">
function loop(e) {
var data = JSON.parse(e.data);
var i = parseInt(data.i, 10);
var iterations = parseInt(data.iterations, 10);
while (iterations % ++i !== 100 && i <= iterations);
if(i <= iterations) {
self.postMessage(JSON.stringify({ i: i, iterations: iterations }));
}
}
self.onmessage = function(e) {
loop(e);
};
</script>
The code:
var ww = document.querySelector('script[type="text/ww"]'),
code = ww.textContent,
blob = new Blob([code], {type: 'text/javascript'}),
blobUrl = URL.createObjectURL(blob),
worker = new Worker(blobUrl);
worker.onmessage = function(e) {
var data = JSON.parse(e.data);
var i = parseInt(data.i, 10);
var iterations = parseInt(data.iterations, 10);
progressbar.set(i);
worker.postMessage(JSON.stringify({ i: i, iterations: iterations }));
}
$('#start_button').on('click', function () {
var iterations = 1000000000;
progressbar.progress_max = iterations;
worker.postMessage(JSON.stringify({ i: 0, iterations: iterations }));
});
The other idea hangs the UI thread, but changes the width visually, as I use requestAnimationFrame to break the counting, change width of the progressbar, and then continue the count.
function loopFrame(i, iterations) {
requestAnimationFrame(function() {
if (iterations % i === 100) {
progressbar.set(i);
}
if(i < iterations) {
loopFrame(i + 1, iterations);
}
});
}
$('#start_button').on('click', function () {
var iterations = 1000000000;
console.log(iterations);
progressbar.progress_max = iterations;
loopFrame(0, iterations);
});

Maybe this will be usefull.
var service = new Object();
//function with interrupt for show progress of operations
service.progressWhile = new Object();
service.progressWhile.dTime = 50; //step ms between callback display function
service.progressWhile.i = 0; //index
service.progressWhile.timer = 0; //start time for cycle
//#parametr arr - array for actions
//#parametr actionCallback - The function for processing array's elements
//#parametr progressCallback - function to display the array index
function progressWhile(arr, actionCallback, progressCallback) {
try {
var d = new Date();
service.progressWhile.timer = d.getTime();
log(service.progressWhile.i);
if (service.progressWhile.i >= arr.length) {
service.progressWhile.i = 0;
return;
}
while (service.progressWhile.i < arr.length) {
actionCallback(arr[service.progressWhile.i++]);
d = new Date();
if (d.getTime() - service.progressWhile.timer > service.progressWhile.dTime) {
break;
}
}
if (progressCallback != undefined)
progressCallback(service.progressWhile.i);
} catch (er) {
log(er);
return;
}
setTimeout(function () {
progressWhile(arr, actionCallback, progressCallback);
}, 0);
}

Here's updated fiddle
I used animate to make it a progress bar like look and feel.
Hope this will help you.
var progressbar = {};
$(function() {
progressbar = {
/** initial progress */
progress : 0,
/** maximum width of progressbar */
progress_max : 0,
/** The inner element of the progressbar (filled box). */
$progress_bar : $('#progressbar'),
/** Method to set the progressbar.*/
set : function(num) {
if (this.progress_max && num) {
this.progress = num / this.progress_max * 100;
console.log('percent: ' + this.progress + '% - ' + num + '/' + this.progress_max);
$('#progressbar').animate({
width : String(this.progress) + '%',
}, 500, function() {
// Animation complete.
});
}
},
fn_wrap : function(num) {
setTimeout(function() {
this.set(num);
}, 0);
}
};
});
$('#start_button').on('click', function() {
$('#progressbar').css('width', '0%');
var iterations = 1000000000;
progressbar.progress_max = iterations;
var loop = function() {
for (var i = 1; i <= iterations; i++) {
if (iterations % i === 100) {
progressbar.set(i);
//only updates the progressbar in the last iteration
}
}
}
loop();
});
Fiddler
[1]: https://jsfiddle.net/k29qy0do/21/

Related

Delay inside for loop not working

I want to make a delay inside my for loop, but it won't really work.
I've already tried my ways that are on stackoverflow, but just none of them work for what I want.
This is what I've got right now:
var iframeTimeout;
var _length = $scope.iframes.src.length;
for (var i = 0; i < _length; i++) {
// create a closure to preserve the value of "i"
(function (i) {
$scope.iframeVideo = false;
$scope.iframes.current = $scope.iframes.src[i];
$timeout(function () {
if ((i + 1) == $scope.iframes.src.length) {
$interval.cancel(iframeInterval);
/*Change to the right animation class*/
$rootScope.classess = {
pageClass: 'nextSlide'
}
currentId++;
/*More information about resetLoop at the function itself*/
resetLoop();
} else {
i++;
$scope.iframes.current = $scope.iframes.src[i];
}
}, $scope.iframes.durationValue[i]);
}(i));
}
alert("done");
This is what I want:
First of all I got an object that holds src, duration and durationValue.
I want to play both video's that I have in my object.
I check how many video's I've got
I make iframeVideo visible (ngHide)
I insert the right <iframe> tag into my div container
It starts the $timeout with the right duration value
If that's done, do the same if there is another video. When it was the last video it should fire some code.
I hope it's all clear.
I've also tried this:
var iframeInterval;
var i = 0;
$scope.iframeVideo = false;
$scope.iframes.current = $scope.iframes.src[i];
iframeInterval = $interval(function () {
if ((i + 1) == $scope.iframes.src.length) {
$interval.cancel(iframeInterval);
/*Change to the right animation class*/
$rootScope.classess = {
pageClass: 'nextSlide'
}
currentId++;
/*More information about resetLoop at the function itself*/
resetLoop();
} else {
i++;
$scope.iframes.current = $scope.iframes.src[i];
}
}, $scope.iframes.durationValue[i])
Each $timeout returns a different promise. To properly cancel them, you need to save everyone of them.
This example schedules several subsequent actions starting at time zero.
var vm = $scope;
vm.playList = []
vm.playList.push({name:"video1", duration:1200});
vm.playList.push({name:"video2", duration:1300});
vm.playList.push({name:"video3", duration:1400});
vm.playList.push({name:"video4", duration:1500});
vm.watchingList=[];
var timeoutPromiseList = [];
vm.isPlaying = false;
vm.start = function() {
console.log("start");
//ignore if already playing
if (vm.isPlaying) return;
//otherwise
vm.isPlaying = true;
var time = 0;
for (var i = 0; i < vm.playList.length; i++) {
//IIFE closure
(function (i,time) {
console.log(time);
var item = vm.playList[i];
var p = $timeout(function(){playItem(item)}, time);
//push each promise to list
timeoutPromiseList.push(p);
})(i,time);
time += vm.playList[i].duration;
}
console.log(time);
var lastPromise = $timeout(function(){vm.stop()}, time);
//push last promise
timeoutPromiseList.push(lastPromise);
};
Then to stop, cancel all of the $timeout promises.
vm.stop = function() {
console.log("stop");
for (i=0; i<timeoutPromiseList.length; i++) {
$timeout.cancel(timeoutPromiseList[i]);
}
timeoutPromiseList = [];
vm.isPlaying = false;
};
The DEMO on PLNKR.
$timeout returns promise. You can built a recursive chain of promises like this, so every next video will play after a small amount of time.

how to use setTimeout or setInterval properly

I am using google maps and i am trying to put a pause in execution to prevent QUERY_LIMIT usage issue. My function that plots the addresses looks like this.
The code works, however i want to try setTimeout or setInterval to see if its going to look better on UI.
How do i call it, what should be the first argument?
Thanx alot.
vLocations = [];
for (var i = 0; i < vAddresses.length; i++) {
//pause to prevent OVER_QUERY_LIMIT issue
//geocode "free" usage limit is 5 requests per second
//setTimeout(PlotAddressesAsUnAssigned, 1000);
//sleep(500);
//this will resolve the address and store it in vLocations
AddWaypointAndUnassigned(vAddresses[i]);
var z = i % 4;
if (z==0 && i != 0) {
//sleep after every 5th geocode call
//alert('going to sleep...i: ' + i);
//sleep(3000);
}
}
Doing a pause (asynchronous execution) inside a loop (synchronous) will usually result in a lot of trouble.
You can use recursive calls that are done only when a timeout ends.
var vLocations = [];
// Manages the timeout and recursive calls
function AddWaypointAndUnassignedWithPause(index){
setTimeout(function(){
// When the timeout expires, we process the data, and start the next timeout
AddWaypointAndUnassigned(vAddresses[index]);
// Some other code you want to execute
var z = i % 4;
if (z==0 && i != 0) {
//sleep after every 5th geocode call
//alert('going to sleep...i: ' + i);
//sleep(3000);
}
if(index < vAddresses.length-1)
AddWaypointAndUnassignedWithPause(++index);
}, 1000);
}
// Start the loop
AddWaypointAndUnassignedWithPause(0);
JSFiddle example.
Try this, hope this will help
vLocations = [];
for (var i = 0; i < vAddresses.length; i++) {
//pause to prevent OVER_QUERY_LIMIT issue
setTimeout(function(){
//this will resolve the address and store it in vLocations
AddWaypointAndUnassigned(vAddresses[i]);
}, 500);
var z = i % 4;
if (z==0 && i != 0) {
//sleep after every 5th geocode call
//alert('going to sleep...i: ' + i);
//sleep(3000);
}
}
What about a waiting line, thats fired when an item is added and stopped when there are no items left.
With setTimeout:
var INTERVAL = 1000 / 5;
var to = null;
var vLocations = [];
function addAddress(vAddress) {
vLocations.push(vAddress);
startTimeout();
}
function startTimeout() {
if( to === null ) {
to = setTimout(processLocation, INTERVAL);
}
}
function processLocation() {
if( vLocations.length ) {
var vAddress = vLocations.shift();
AddWaypointAndUnassigned(vAddress);
to = setTimout(processLocation, INTERVAL);
} else {
to = null;
}
}
With setInterval:
var INTERVAL = 1000 / 5;
var to = null;
var vLocations = [];
function addAddress(vAddress) {
vLocations.push(vAddress);
startInterval();
}
function startInterval() {
if( to === null ) {
to = setInterval(processLocation, INTERVAL);
}
}
function processLocation(cb) {
if( vLocations.length ) {
var vAddress = vLocations.shift();
AddWaypointAndUnassigned(vAddress);
} else
clearInterval(to);
to = null;
}
}

$.each not updating css width

So I have a loop, which performs an ajax call on each iteration and I want to set the progress bar updated.. But it is not updating, it goes to 100% directly when ending...
I've tried to put the bar update call outside the success action (inside the loop directly) but it isn't working either..
$('button.page').on('click', function(e){
var $userList = textArray($('#page-userlist').val().replace('http://lop/', '').split(/\n/));
var $proxyList = textArray($('#page-proxylist').val().replace('http://', '').split(/\n/));
var $question = $('#page-question').val();
var data = {
question: $question,
users: $userList,
proxies: $proxyList
};
var i = 0, p = 0, max = data.proxies.length, totalusers = data.users.length, percent = 0;
$('#log').append("\n" + moment().calendar() + "\n");
var progressbar = $('#page-progress');
$.each(data.users, function(k, u){
if(typeof(p) !== 'undefined' && p !== null && p > 0)
{
if(i % 10 == 0 && i > 1) p++;
if(p == max) return false;
}
var proxy = data.proxies[p];
percent = Math.round((i / totalusers) * 100);
$.ajax({
type: "POST",
url: Routing.generate('viral_admin_bot_page'),
data: {question: $question, user: u, proxy: proxy},
success: function(result) {
$('#log').append("\nAtacado usuario " + u + " con proxy: " + proxy + "\n");
$(progressbar).width(percent + "%");
},
error: function(error) {
$('#log').append(error);
}
});
i++;
});
});
If i do console.log(percent); it is updating perfectly on each iteration, so I don't know where can be the problem.
Here is my code (without the ajax call because it isn't the problem) http://jsfiddle.net/dvo1dm03/20/
it will output to console the percentage, the objetive is to update the bar to the percentage completed in each loop, so it goes in "realtime" with loop.
Ok, here's how to do it asynchrounously.
var speed = 75;
var number_of_calls_returned = 0; // add number_of_calls_returned++ in your ajax success function
var number_of_total_calls;
var loaded = false;
function processUserData(){
if( number_of_calls_returned < number_of_total_calls){
setTimeout(function(){processUserData();}, 200);
}
else{
//received all data
// set progressbar to 100% width
loaded = true;
$("#page-progress").animate({width: "100%"},500);
$("#page-proxylist").val("Received data");
}
}
function updateProgress(percent, obj){
setTimeout(function(x){
if(!loaded)
$(obj).width(x + "%");
}, percent*speed, percent);
}
$('button.page').on('click', function (e) {
var $userList = textArray($('#page-userlist').val().replace('http://lop/', '').split(/\n/));
var $proxyList = textArray($('#page-proxylist').val().replace('http://', '').split(/\n/));
var $question = $('#page-question').val();
var data = {
question: $question,
users: $userList,
proxies: $proxyList
};
var i = 0,
p = 0,
max = data.proxies.length,
totalusers = data.users.length,
percent = 0;
//$('#log').append("\n" + moment().calendar() + "\n");
var progressbar = $('#page-progress');
number_of_total_calls = totalusers;
$.each(data.users, function (k, u) {
if (typeof (p) !== 'undefined' && p !== null && p > 0) {
if (i % 10 == 0 && i > 1) p++;
if (p == max) return false;
}
var proxy = data.proxies[p];
percent = (i / totalusers) * 100; //much smoother if not int
updateProgress(percent, progressbar);
i++;
// simulate ajax call
setTimeout(function(){number_of_calls_returned++;}, Math.random()*2000);
});
//callback function
setTimeout(function(){processUserData();}, 200);
});
var textArray = function (lines) {
var texts = []
for (var i = 0; i < lines.length; i++) {
// only push this line if it contains a non whitespace character.
if (/\S/.test(lines[i])) {
texts.push($.trim(lines[i]));
}
}
return texts;
}
Check it out here! jsFiddle (really cool!)
Your problem is cause by the fact that you have a closure for your success function and every success function shares the same percent variable. You can fix it like this:
success: function(percent, result) {
$('#log').append("\nAtacado usuario " + u + " con proxy: " + proxy + "\n");
$(progressbar).width(percent + "%");
}.bind(percent),
Where you'll need to shim bind in older browsers, or like this, which is a little uglier, but should work everywhere without a shim:
success: (function(percent) { return function(result) {
$('#log').append("\nAtacado usuario " + u + " con proxy: " + proxy + "\n");
$(progressbar).width(percent + "%");
}; }( percent ),
if what you want is to increase the update bar with each success of AJAX calls I'd suggest an easier solution (I've simplified the js code for clarity's sake):
$('button').click(function (e) {
var i = 0,
cont = 0,
totalusers = 100,
percent = 0;
var progressbar = $('#page-progress');
for (; i < totalusers; i++) {
$.ajax({
type: "POST",
url: '/echo/json/',
data: {
question: 'something',
user: 1,
proxy: 2
},
success: function (result) {
cont += 1;
percent = Math.round((cont / totalusers) * 100);
progressbar.width(percent + "%");
},
error: function (error) {
$('#log').append(error);
}
});
};
});
You can see it in action in this fiddle.
Hope this helps or at least give you some ideas.
Update the progress bar using setTimeout method.
it will wait for some time and then update the width of progressbar.
myVar = setTimeout("javascript function",milliseconds);
Thanks,
Ganesh Shirsat
I would like to make a recommendation of trying to make a self contained example that doesn't rely on the post so that it is easier for you or us to solve the problem
As well, you can console log elements so you could try logging the progressbar element, percent and the response of the ajax request
(This code is to replace the javascript sections of the fiddler)
var i = 0;
moveProgress();
function moveProgress(){
if(i < 10000)
{
setTimeout(function(){
$('#page-progress').width((i / 1000) * 100);
moveProgress();
},2);
i++;
}
}
The reason that it wasn't working was because the loop ran so fast that it was loaded by the time the script loaded it, the timeout allows you to delay the execution a bit(Though not necessarily recommended to use because of potential threading issues.

How to pass a variable after setInterval completes?

I have the following code. A fiddle I started which is an isolated version of something I am trying to do.
var height;
var count = 0;
var setHeight = setInterval(function() {
count++;
console.log('count');
if ( count > 10)
{
console.log('done');
height = 20;
clearInterval(setHeight);
}
},100);
console.log('this is the height -> ' + height);
What I would expect (or want to happen) is for the value of height = 20; to be outputted in my console.log. The end goal would be to retrieve a variable from my setInterval function after the interval has been cleared.
Right now I get .. this is the height -> undefined
FIDDLE:
http://jsfiddle.net/GNvG6/8/
What I am trying to accomplish:
So the underlying issue is this. I have a function that runs before some elements are loaded in the DOM. So what I am trying to do is keep running the function until an instance of that element exists. Once that happens I then intend to get the height of that element and hand it off to another variable. I am not sure If this will resolve my issue, but I figure if I can get this to work I can at least test it out.
var height;
var count = 0;
var setHeight = setInterval(function() {
count++;
console.log('count');
if ( count > 10)
{
console.log('done');
height = 20;
reportHeight(height);
clearInterval(setHeight);
}
},100);
function reportHeight(height){
console.log('this is the height -> ' + height);
}
console output is
(11) count
done
this is the height -> 20
FIDDLE DEMO
var height = 0; // initial value
var count = 0;
var setHeight = setInterval(function() {
count++;
console.log('count and height is still:'+ height); // height is always 0
if ( count > 10){
height = 20;
console.log('done and height is:'+ height); // height is finally 20
clearInterval(setHeight);
}
},100);
As you're using jQuery, you could also use $.Deferred.
// wait for 3 + (0..2) seconds
setTimeout(function () {
$(document.body).append($("<strong>hello</strong>"));
}, 3000 + 2000 * Math.random());
function waitFor(test, interval) {
var dfd = $.Deferred();
var count = 0;
var id = setInterval(function () {
console.log(count++);
var val = test();
if (undefined !== val) {
clearInterval(id);
dfd.resolve(val);
}
}, interval);
return dfd.promise();
}
function waitForEl(selector, interval) {
return waitFor(function () {
var els = $(selector);
return (els.length > 0) ? els : undefined;
}, interval);
}
waitForEl("strong", 100).then(function (strong) {
console.log(strong, strong.height());
});
Example in this jsfiddle.

How do I update the html displayed for each iteration of a for loop in javascript / jquery?

How would I have the h1 change for each iteration of the loop? This code now only displays the h1 text after everything is done.
for (i=0; i<array.length; i++) {
$("body > h1").text("Processing #" + i);
// things that take a while to do
}
Additional info: if I resize the window as it loops, the html updates.
var array = ['one', 'two', 'three']
var i = 0;
var refreshIntervalId = setInterval(function() {
length = array.length;
if (i < (array.length +1)) {
$("h1").text("Processing #" + i);
} else {
clearInterval(refreshIntervalId);
}
i++
}, 1000);
http://jsfiddle.net/3fj9E/
Use a setInterval with a one-millisecond delay:
var i=0, j=array.length;
var iv = setInterval(function() {
$("h1").text("Processing #" + i);
// things that take a while to do
if (++i>=j) clearInterval(iv);
}, 1);
http://jsfiddle.net/mblase75/sP9p7/
Sometimes you can force a render by forcing a recalculation of layout
for (i=0; i<array.length; i++) {
$("body > h1").text("Processing #" + i)
.width(); // force browser to recalculate layout
// things that take a while to do
}
It might not work in all browsers.
A better way, that does not block the browser so much:
function doThings(array) {
var queueWork,
i = -1,
work = function () {
// do work for array[i]
// ...
queueWork();
};
queueWork = function () {
if (++i < array.length) {
$("body > h1").text("Processing #" + i);
setTimeout(work, 0); // yield to browser
}
};
}
doThings(yourArray);
DEMO
I've spent a bit of time working out a jquery function that seems to solve this. Basically, it's a process handler that you can add any number of processes to and then call run to sequentially call these in a asynchronous way.
$.fn.LongProcess = function () {
var _this = this;
this.notifications = [];
this.actions = [];
this.add = function (_notification, _action) {
this.notifications.push(_notification);
this.actions.push(_action);
};
this.run = function () {
if (!_this.actions && !_this.notifications) {
return "Empty";
}
//******************************************************************
//This section makes the actions lag one step behind the notifications.
var notification = null;
if (_this.notifications.length > 0) notification = _this.notifications.shift();
var action = null;
if ((_this.actions.length >= _this.notifications.length + 2) || (_this.actions.length > 0 && _this.notifications.length == 0))
action = _this.actions.shift();
//****************************************************************
if (!action && !notification) {
return "Completed";
}
if (action) action();
if (notification) notification();
setTimeout(_this.run, 1000);
//setTimeout(_this.run,1); //set to 1 after you've entered your actual long running process. The 1000 is there to just show the delay.
}
return this;
};
How to use with <h1 class="processStatus"></h1>:
$(function () {
var process = $().LongProcess();
//process.add(notification function, action function);
process.add(function () {
$(".processStatus").text("process1");
}, function () {
//..long process stuff
alert("long process 1");
});
process.add(function () {
$(".processStatus").text("process2");
}, function () {
//..long process stuff
alert("long process 2");
});
process.add(function () {
$(".processStatus").text("process3");
}, function () {
//..long process stuff
alert("long process 3");
});
process.run();
});
if the process is very long you can use this script which shows every notification for a specific time interval.
here is the code..
html
<div id="ccNotificationBox"></div>
css
#ccNotificationBox{
-webkit-animation-name:;
-webkit-animation-duration:2s;/*Notification duration*/
box-sizing:border-box;
border-radius:16px;
padding:16px;
background-color:rgba(0,0,0,0.7);
top:-100%;
right:16px;
position:fixed;
color:#fff;
}
#ccNotificationBox.active{
-webkit-animation-name:note;
top:16px;
}
#-webkit-keyframes note{
0% {opacity:0;}
20% {opacity:1;}
80% {opacity:1;}
100% {opacity:0;}
}
javascript
var coccoNotification=(function(){
var
nA=[],
nB,
rdy=true;
function nP(a){
nA.push(a);
!rdy||(nR(),rdy=false);
}
function nR(){
nB.innerHTML=nA[0];console.log(nA[0]);
nB.offsetWidth=nB.offsetWidth;//reflow ios
nB.classList.add('active');
}
function nC(){
nB.classList.remove('active');
nB.innerHTML='';
nA.shift();
nA.length>0?nR():(rdy=true);
}
function init(){
nB=document.getElementById('ccNotificationBox');
nB.addEventListener('webkitAnimationEnd',nC,false);
window.removeEventListener('load',init,false);
}
window.addEventListener('load',init,false);
return nP
})();
usage
coccoNotification('notification 1');
example
http://jsfiddle.net/f6dkE/1/
info
the example above is perfect for external js as you use just one global variable which is the name of the function ... in my case coccoNotification
here is a different approach but it does the same
http://jsfiddle.net/ZXL4q/11/

Categories