ember-sortable

Ember-sortable

Sortable UI primitives for Ember.

ember-sortable in action

Migration

If you are migrating from 1.x.x to 2.x.x. Please read this migration guide.

Requirements

In version 2.0.0+, our closest polyfill seems to break some app’s production build. To mitigate this, the closest polyfill will only enabled if it doesn’t break the production build (if the polyfill file is recognized by the build). Affected apps will need to supply their own closest polyfill to ensure compatibility with IE. This issue is tracked here.

Version 1.0 depends upon the availability of 2D CSS transforms. Check the matrix on caniuse.com to see if your target browsers are compatible.

Installation

$ ember install ember-sortable

Usage

  
        <span class="handle">&varr;</span>

The onChange action is called with two arguments:

Your item models in their new order
The model you just dragged

// app/routes/my-route.js

export default Ember.Route.extend({
  actions: {
    reorderItems(itemModels, draggedModel) {
      this.set('currentModel.items', itemModels);
      this.set('currentModel.justDragged', draggedModel);
    }
  }
});

Declaring a “group model”

When groupModel is set on the sortable-group, the onChange action is called with that group model as the first argument:

  
        <span class="handle">&varr;</span>

// app/routes/my-route.js

export default Ember.Route.extend({
  actions: {
    reorderItems(groupModel, itemModels, draggedModel) {
      groupModel.set('items', itemModels);
    }
  }
});

Changing sort direction

To change sort direction, define direction on sortable-group (default is y):

Changing spacing between currently dragged element and the rest of the group

When user starts to drag element, other elements jump back. Works both for the x and y direction option.

In y case: elements above current one jump up, and elements below current one - jump down. In x case: elements before current one jump to the left, and elements after current one - jump to the right.

To change this property, define spacing on sortable-item (default is 0):

Changing the drag tolerance

distance attribute changes the tolerance, in pixels, for when sorting should start. If specified, sorting will not start until after mouse is dragged beyond distance. Can be used to allow for clicks on elements within a handle.

CSS, Animation

Sortable items can be in one of three states: default, dragging, dropping. The classes look like this:

<!-- Default -->
<li class="sortable-item">...</li>
<!-- Dragging -->
<li class="sortable-item is-dragging">...</li>
<!-- Dropping -->
<li class="sortable-item is-dropping">...</li>

In our example app.css we apply a transition of .125s in the default case:

.sortable-item {
  transition: all .125s;
}

While an item is dragging we want it to move pixel-for-pixel with the user’s mouse so we bring the transition duration to 0. We also give it a highlight color and bring it to the top of the stack:

.sortable-item.is-dragging {
  transition-duration: 0s;
  background: red;
  z-index: 10;
}

While dropping, the is-dragging class is removed and the item returns to its default transition duration. If we wanted to apply a different duration we could do so with the is-dropping class. In our example we opt to simply maintain the z-index and apply a slightly different colour:

.sortable-item.is-dropping {
  background: #f66;
  z-index: 10;
}

Drag Actions

The onDragStart and onDragStop actions are available for the sortable-items. You can provide an action name to listen to these actions to be notified when an item is being dragged or not.

When the action is called, the item’s model will be provided as the only argument.

// app/routes/my-route.js

export default Ember.Route.extend({
  actions: {
    dragStarted(item) {
      console.log(`Item started dragging: ${item.get('name')}`);
    },
    dragStopped(item) {
      console.log(`Item stopped dragging: ${item.get('name')}`);
    }
  }
});

  
      <span class="handle">&varr;</span>

Data down, actions up

No data is mutated by sortable-group or sortable-item. In the spirit of “data down, actions up”, a fresh array containing the models from each item in their new order is sent via the group’s onChange action.

sortable-group yields itself to the block so that it may be assigned explicitly to each item’s group property.

Each item takes a model property. This should be fairly self-explanatory but it’s important to note that it doesn’t do anything with this object besides keeping a reference for later use in onChange.

Accessibility

The sortable-group has support for the following accessibility functionality:

Built-in Functionalities

Semantic HTML

sortable-group an ordered list, ol, by default.
sortable-item a list item, li, by default.

There are 4 modes during keyboard navigation:

ACTIVATE enables the keyboard navigation. Activate via ENTER/SPACE
MOVE enables item(s) to be moved up, down, left, or right based on direction. Activate via ARROW UP/DOWN/LEFT/RIGHT
CONFIRM submits the new sort order, invokes the onChange action. Activate via ENTER/SPACE.
CANCEL cancels the new sort order, reverts back to the old sort order. Activate via ESCAPE or when focus is lost.

Focus Management

When focus is on a item or handle, user can effectively select the item via ENTER/SPACE. This is the ACTIVATE mode.
While ACTIVATE, the focus is locked on sortable-group container and will not be lost until CONFIRM, CANCEL, or focus is lost.

User configurable

a11yItemName a name for the item.

a11yAnnouncementConfig a map of action enums to functions that takes the following config, which is exposed by sortable-group.

a11yAnnounceConfig = {
a11yItemName, // name associated with the name
index, // 0-based
maxLength, // length of the items
direction, // x or y
delta, // +1 means down or right, -1 means up or left
}

and returns a string constructed from the config.

Example

{
  ACTIVATE: function({ a11yItemName, index, maxLength, direction }) {
    let message = `${a11yItemName} at position, ${index + 1} of ${maxLength}, is activated to be repositioned.`;
    if (direction === 'y') {
      message += 'Press up and down keys to change position,';
    } else {
      message += 'Press left and right keys to change position,';
    }

    message += ' Space to confirm new position, Escape to cancel.';

    return message;
  },
  MOVE: function({ a11yItemName, index, maxLength, delta }) {
    return `${a11yItemName} is moved to position, ${index + 1 + delta} of ${maxLength}. Press Space to confirm new position, Escape to cancel.`;
  },
  CONFIRM: function({ a11yItemName}) {
    return `${a11yItemName} is successfully repositioned.`;
  },
  CANCEL: function({ a11yItemName }) {
    return `Cancelling ${a11yItemName} repositioning`;
  }
}

Visual Indicator

handleVisualClass This class will be added to the sortable-handle during ACTIVATE and MOVE operations. This allows you to add custom styles such as visual arrows via pseudo classes.
itemVisualClass This class will be added to the sortable-item during ACTIVATE and MOVE operations. This is needed to creating a visual indicator that mimics focus b/c the native focus is on the container.

Testing

ember-sortable exposes some acceptance test helpers:

drag: Drags elements by an offset specified in pixels.
reorder: Reorders elements to the specified state.
keyboard: Keycode constants for quick.

To include them in your application, you can import them:

import { drag, reorder }  from 'ember-sortable/test-support/helpers';
import { ENTER_KEY_CODE, SPACE_KEY_CODE, ESCAPE_KEY_CODE, ARROW_KEY_CODES } from "ember-sortable/test-support/utils/keyboard";

Examples

Reorder

await reorder(
  'mouse',
  '[data-test-vertical-demo-handle]',
  ...order
);

Drag

await drag('mouse', '[data-test-scrollable-demo-handle] .handle', () => { return {dy: itemHeight() * 2 + 1, dx: undefined}});

Keyboard

await triggerKeyEvent(
  '[data-test-vertical-demo-handle]',
  'keydown',
  ENTER_KEY_CODE
);

Developing

Setup

$ git clone git@github.com:adopted-ember-addons/ember-sortable
$ cd ember-sortable
$ ember install

Dev Server

$ ember serve

Running Tests

$ npm test

Publishing Demo

$ make demo

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