ngx-sortablejs

This package is an Angular 2+ binding for Sortable.js. Supports standard arrays and Angular FormArray.

Previously known as angular-sortablejs.

Demo

See the library in action in a demo project (the source is located in src directory).

Trees are also supported: tree with fake root element (*ngFor once, root can also be hidden anyway) or without (*ngFor 2 times).

Installation

npm i -S ngx-sortablejs sortablejs
npm i -D @types/sortablejs

You are configured now. If you use Webpack or Angular CLI go to the usage. If you have SystemJS, that's sad, but you can go to the end of the document to find configuration steps there.

Usage

First, import SortablejsModule.forRoot({ /* and here some global settings if needed */ }) into the root module of your application:

imports: [
  // ...
  SortablejsModule.forRoot({ animation: 150 }),
  // ...
]

Then import SortablejsModule into the other angular modules where you want to use it:

imports: [
  // ...
  SortablejsModule,
  // ...
]

Then use sortablejs property on a container HTML element to tell Angular that this is a sortable container; also pass the items array to both *ngFor and [sortablejs] to register the changes automatically.

Directive API

• sortablejs - directive, accepts model to be auto-updated (see examples below)
• sortablejsContainer - directive input, CSS selector for the sortable container, string. Mostly required for frameworks that wrap the content into the elements where it is impossible to access the real container element (e.g. @angular/material). Example: sortablejsContainer=".mat-grid-list"
• sortablejsOptions - directive input, sortable options to pass in. Please note that in order to change the options later the whole object needs to be recreated, see below
• sortablejsInit - directive output, returns the current Sortable instance. Example: (sortablejsInit)="sortableInstance = $event"

Simple sortable list

import { Component } from '@angular/core';

@Component({
    selector: 'my-app',
    template: `
      <h2>Drag / drop the item</h2>
      <div [sortablejs]="items">
        <div *ngFor="let item of items">{{ item }}</div>
      </div>
    `
})
export class AppComponent {
   items = [1, 2, 3, 4, 5];
}

Passing the options

Pass the options with sortablejsOptions property.

import { Component } from '@angular/core';

@Component({
    selector: 'my-app',
    template: `
      <h2>Drag / drop the item</h2>
      <div [sortablejs]="items" [sortablejsOptions]="{ animation: 150 }">
        <div *ngFor="let item of items">{{ item }}</div>
      </div>
    `
})
export class AppComponent {
   items = [1, 2, 3, 4, 5];
}

Tracking lists update events

You can use the options' onUpdate method to track the changes (see also Passing the options section):

constructor() {
  this.options = {
    onUpdate: (event: any) => {
      this.postChangesToServer();
    }
  };
}

If you use FormArray you are able to choose a more elegant solution:

public items = new FormArray([
  new FormControl(1),
  new FormControl(2),
  new FormControl(3),
]);

constructor() {
  this.items.valueChanges.subscribe(() => {
    this.postChangesToServer(this.items.value);
  });
}

but note, that here you will be able to take the whole changed array only (no oldIndex / newIndex).

Updating the options

You can pass a new options object at anytime via the [sortablejsOptions] binding and the Angular's change detection will check for the changes from the previous options and will call the low level option setter from Sortable.js to set the new option values.

Note: It will only detect changes when a brand new options object is passed, not deep changes.

Drag & drop between two lists

The only thing which should be done is assigning the group option to the both list. Everything else is handled automatically.

import { Component } from '@angular/core';
import { SortablejsOptions } from 'ngx-sortablejs';

@Component({
    selector: 'my-app',
    template: `
    <h2>Drag / drop the item</h2>
    <h3>list 1</h3>
    <div class="items1" [sortablejs]="items1" [sortablejsOptions]="options">
      <div *ngFor="let item of items1">{{ item }}</div>
    </div>
    <h3>list 2</h3>
    <div class="items2" [sortablejs]="items2" [sortablejsOptions]="options">
      <div *ngFor="let item of items2">{{ item }}</div>
    </div>
    `
})
export class AppComponent {
   items1 = [1, 2, 3, 4, 5];
   items2 = ['a', 'b', 'c', 'd', 'e'];

   options: SortablejsOptions = {
     group: 'test'
   };
}

Drag & drop between two lists: clone mode

The clone mode is similar to the one above (of course the proper Sortablejs settings should be used; see demo). The only important thing is that the ngx-sortablejs does clone the HTML element but does not clone the variable (or FormControl in case of FormArray input). By default the variable will be taken as is: a primitive will be copied, an object will be referenced.

If you want to clone the item being sorted in a different manner, you can provide sortablejsCloneFunction as a parameter. This function receives an item and should return a clone of that item.

import { Component } from '@angular/core';
import { SortablejsOptions } from 'ngx-sortablejs';

@Component({
    selector: 'my-app',
    template: `
    <h2>Drag / drop the item</h2>
    <h3>list 1</h3>
    <div class="items1" [sortablejs]="items1" [sortablejsOptions]="options" [sortablejsCloneFunction]="myCloneImplementation">
      <div *ngFor="let item of items1">{{ item }}</div>
    </div>
    <h3>list 2</h3>
    <div class="items2" [sortablejs]="items2" [sortablejsOptions]="options" [sortablejsCloneFunction]="myCloneImplementation">
      <div *ngFor="let item of items2">{{ item }}</div>
    </div>
    `
})
export class AppComponent {

  myCloneImplementation = (item) => {
    return item; // this is what happens if sortablejsCloneFunction is not provided. Add your stuff here
  }

}

Bind events inside Angular zone

By default, the boolean parameter runInsideAngular is set to false. This means that the initial binding of all mouse events of the component will be set so that they will not trigger Angular's change detection.

If this parameter is set to true, then for large components - with a lot of data bindings - the UI will function in a staggered and lagging way (mainly when dragging items), while every event will trigger the change detection (which might be needed in some special edge cases).

Configure the options globally

If you want to use the same sortable options across different places of your application you might want to set up global configuration. Add the following to your main module to enable e.g. animation: 150 everywhere:

imports: [
  // ...
  // any properties and events available on original library work here as well
  SortablejsModule.forRoot({
    animation: 150
  }),
  // ...
]

This value will be used as a default one, but it can be overwritten by a local sortablejsOptions property.

Angular Material specifics

Expansion panel

There is a bug with expansion panel which appears because angular material does not really hide the content of panel, but uses visibility: hidden. What we need to do is to actually totally hide it from the DOM instead.

Just add this to your global styles

mat-expansion-panel.sortable-drag .mat-expansion-panel-content {
  display: none;
}

and the issue should be resolved.

Ripple effect

The elements with ripple effect like mat-list-item are affected. The dragging is broken because there is a div created right under the cursor and the webkit has no idea what to do with it.

There are two solutions:

1. Disable the ripple effect

<a mat-list-item [disableRipple]="true">

2. Use handle property and block propagation of mousedown and touchstart events on the handler to prevent ripple.

<div [sortablejs]="..." [sortablejsOptions]="{ handle: '.handle' }">
  <a mat-list-item *ngFor="let a of b" [routerLink]="..." routerLinkActive="active">
    <mat-icon matListIcon
              class="handle"
              (mousedown)="$event.stopPropagation()"
              (touchstart)="$event.stopPropagation()">drag_handle</mat-icon> {{ a }}
  </a>
</div>

How it works

The model is automatically updated because you pass the items as <div [sortablejs]="items">. The items variable can be either an ordinary JavaScript array or a reactive forms FormArray.

If you won't pass anything, e.g. <div sortablejs>, the items won't be automatically updated, thus you should take care of updating the array on your own using standard Sortable.js events.

Original events onAdd, onRemove, onUpdate are intercepted by the library in order to reflect the sortable changes into the data. If you will add your own event handlers (inside of the options object) they will be called right after the data binding is done. If you don't pass the data, e.g. <div sortablejs> the data binding is skipped and only your event handlers will be fired.

Important: the original onAdd event happens before the onRemove event because the original library makes it like that. We change this behavior and call 'onAdd' after the 'onRemove'. If you want to work with original onAdd event you can use onAddOriginal which happens before onRemove.

License

MIT