JQuery UI Sortable performance while sorting

jqueryjquery-uijquery-ui-sortable

I have a calendar being used in production with 60 days and up to 5 sortable items per day, so that's 300 sortable items. The days are <td> elements and the events are <div>s.

Both sorting within a day and dragging from one day to another are slow. The element freezes up for a bit when it enters a new day or when it passes over another sortable item.

The delay seems related to both the number of days and the number of sortable items.

Here is the jQuery code.

$('.calendar-schedule-day').sortable({
    items: ".service-trip, .calendar-event",
    connectWith: ".calendar-schedule-day"
});

How can I reduce the delay that occurs when sorting?

More info

Where chrome is calling Layout and RecalculateStyle many times in a row, there is the following warning:

Layout – Details
Duration 15.000 ms (at 36.86 s)
Note Forced synchronous layout is a possible performance bottleneck.
Layout invalidated
….

Update: jsFiddle here – it is so unusably slow that I can't tell if it reproduces the problem or not. It is not like that in production. But if I start removing html (like weeks) from the example then I may not be able to reproduce the problem anyway.

Best Answer

Seems i got it a lot faster by hiding all sortable elements before calling sortable and after it i show them again.

$('.calendar-schedule-day').hide();
$('.calendar-schedule-day').sortable({ ... });
$('.calendar-schedule-day').sortable({ connectWith: ... });
$('.calendar-schedule-day').show();

JSFiddle

Better way to fix it

just use this selector $('.calendar-schedule-day:visible') instead of $('.calendar-schedule-day') when using .sortable()

JSFiddle

Seems that the hide elements messes with sortable, so we will only make the visible elements sortable.

Related Solutions

Javascript – n “exists” function for jQuery

In JavaScript, everything is 'truthy' or 'falsy', and for numbers 0 means false, everything else true. So you could write:

if ($(selector).length)

You don't need that >0 part.

Javascript – Add table row in jQuery

The approach you suggest is not guaranteed to give you the result you're looking for - what if you had a tbody for example:

<table id="myTable">
  <tbody>
    <tr>...</tr>
    <tr>...</tr>
  </tbody>
</table>

You would end up with the following:

<table id="myTable">
  <tbody>
    <tr>...</tr>
    <tr>...</tr>
  </tbody>
  <tr>...</tr>
</table>

I would therefore recommend this approach instead:

$('#myTable tr:last').after('<tr>...</tr><tr>...</tr>');

You can include anything within the after() method as long as it's valid HTML, including multiple rows as per the example above.

Update: Revisiting this answer following recent activity with this question. eyelidlessness makes a good comment that there will always be a tbody in the DOM; this is true, but only if there is at least one row. If you have no rows, there will be no tbody unless you have specified one yourself.

DaRKoN_ suggests appending to the tbody rather than adding content after the last tr. This gets around the issue of having no rows, but still isn't bulletproof as you could theoretically have multiple tbody elements and the row would get added to each of them.

Weighing everything up, I'm not sure there is a single one-line solution that accounts for every single possible scenario. You will need to make sure the jQuery code tallies with your markup.

I think the safest solution is probably to ensure your table always includes at least one tbody in your markup, even if it has no rows. On this basis, you can use the following which will work however many rows you have (and also account for multiple tbody elements):

$('#myTable > tbody:last-child').append('<tr>...</tr><tr>...</tr>');

Best Answer

Related Solutions

Javascript – n “exists” function for jQuery

Javascript – Add table row in jQuery

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