Angular dragtable

Angular dragtable

Angular dragtable is an Angular directive that allows table column reorder.

I’ve been searching for a similar solution, including JavaScript libraries, jQuery plugins or Angular directives. I’ve tested various solutions, but nothing worked as expected. So I decided to create brand new directive.

The package is available here.
And the demo is available here.

Angular dragtable events

Angular dragtable uses drag events. Drag events are around for a while and have a pretty good support. There are some issues, but nothing that cannot be solved. It should be noted that the drag events do not work on mobile devices. Although I thought about implementing mobile support using touch events or excellent jQuery UI Touch Punch plugin, I give up at the end. This feature is not crucial on mobile devices. Even if I did provide mobile implementation, it could be really hard to use this feature.

The main idea of Angular dragtable directive is to reorder the table columns by dragging table header cell. We have to listen when drag event starts and when it ends. When dragging occurs we should display ghost floating table column as a current position indicator. Angular dragtable actually contains 2 directives, one for draggable elements and one for droppable elements. A full code could be found here.

Dragging

If we want to enable draggable events on header cell, we should add drag-me directive by providing it via attribute name. There are 3 main drag events:

  • dragstart - fires when a drag event start;
  • drag - fires during drag event;
  • dragend - fires when a drag event ends.

On dragstart event, we want to remove every ghost elements that are left behind and create new ghost elements for current column.
Actual dragging fires drag event on which we want to move ghost column when we move the mouse. It is always a great idea to set the timeout on events that occur every few hundred milliseconds.
And finally, we will use dragend event to remove ghost column.

Dropping

Dropping events allow us to reorder columns by listening when ghost column is over the current column. To enable droppable events on header cell, we should add drop-me directive. For this purpose, we should use dragover event. This event fires when draggable element is over droppable element.

On dragover event, we want to determine a direction of dragging event and append ghost column before or after current column. This means that we don’t need to listen to drop event because we are responding with a live action on dragover event. That is desirable effect as we want to avoid unnecessary events. Again, we should set timeout here, just like we did on drag event.

Usage

To install Angular dragtable, clone the repository from Github or use bower installer: bower install **angular-dragtable**.

Include Angular dragtable in your project.

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(function (DemoApp) {
'use strict';
DemoApp = angular.module('DemoApp', ['Dragtable']);
DemoApp.config(function () {});
}(this));

To enable reorder of table header cells, use drag-me and drop-me directives.

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<table>
<thead>
<tr>
<th>ID</th>
<th drag-me drop-me>Name</th>
<th drag-me drop-me>Description</th>
<th drag-me drop-me>Age</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td>Item 1</td>
<td>Description 1</td>
<td>1</td>
</tr>
...
</tbody>
</table>

If you want to use a custom handle for drag events, you should provide selector via data-handle attribute.

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<th drag-me drop-me data-handle=".my-handle">
<span class="my-handle drag-icon"></span> Column name
</th>

Be sure to place handle element inside header cell.

To make Angular dragtable more performant, especially when using a large table, we should use data-limit option. When this option is provided, a number of ghost column elements are limited. That means less iteration during drag event.

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<th drag-me drop-me data-limit="50"><th>

Conclusion

In this article, I wanted to provide detailed insight of the creation process of this Angular directive.

I really enjoyed building it and I’m hoping you will enjoy using it.

Share your thoughts by commenting on this article or tweet me.

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