Table of Contents
Dragula is a popular JavaScript library for drag & drop, and ng2-dragula is a wrapper to use Dragula in Angular 2+ apps. Let's see how it's used.
Installation
First add ng2-dragula to your project using Yarn or npm:
# Yarn
$ yarn add ng2-dragula
# npm
$ npm install ng2-dragula --save
Now import <^>DragulaModule<^> and add it to your NgModule's imports:
[label app.module.ts]
// ...
import { DragulaModule } from 'ng2-dragula/ng2-dragula';
And the last setup step is to add the Dragula CSS file to the project. If you're using the Angular CLI, you can simply add the CSS file path in your <^>.angular-cli.json<^> file:
"styles": [
"styles.css",
<^>"../node_modules/dragula/dist/dragula.css"<^>
],
Using ng2-dragula
Now to use it, it's as simple as using the <^>dragula<^> directive on a container element in your template and providing a group name. Groups in Dragula are called bags:
<ul [dragula]='"bag-items"'>
<li *ngFor="let item of items">{{ item }}</li>
</ul>
And if you have multiple distinct containers:
<ul [dragula]='"bag-items"'>
<li *ngFor="let item of items">{{ item }}</li>
</ul>
<ul [dragula]='"bag-people"'>
<li *ngFor="let person of people">{{ person }}</li>
</ul>
—
If you want the changes in order to be synced in your items array, simply use the <^>dragulaModel<^> directive with the name of the model. This way, when items are re-ordered via drag & drop, the items array will also have its items re-ordered to reflect the changes:
<ul [dragula]='"bag-items"' [dragulaModel]='items'>
<li *ngFor="let item of items">{{ item }}</li>
</ul>
Events and Configuration Options
You can use the <^>DragulaService<^> to hook into events or to set configuration options.
Configuration
To use the service, first import it and inject it in the constructor. Then it's as simple as calling the <^>setOptions<^> method, specifying the container and providing an object literal with your desired options:
import { Component, OnInit } from '@angular/core';
import { DragulaService } from 'ng2-dragula/ng2-dragula';
@Component({ ... })
export class AppComponent implements OnInit {
constructor(private dragula: DragulaService) {
this.dragula.setOptions('bag-items', {
revertOnSpill: true
});
}
}
You can set options such as <^>direction<^>, <^>copy<^>, <^>copySortSource<^>, <^>revertOnSpill<^>, <^>removeOnSpill<^> and <^>mirrorContainer<^>. Refer to the project page for configuration options.
Events
You can hook into the <^>drag<^>, <^>drop<^>, <^>over<^> and <^>out<^> events and each of the events return an observable. Here's a complete example where a message is displayed when dragging or dropping an item:
import { Component, OnInit } from '@angular/core';
import { DragulaService } from 'ng2-dragula/ng2-dragula';
@Component({ ... })
export class AppComponent implements OnInit {
msg = '';
items = [
'Candlestick',
'Dagger',
'Revolver',
'Rope',
'Pipe',
'Wrench'
];
constructor(private dragula: DragulaService) { }
ngOnInit() {
this.dragula
<^>.drag<^>
.subscribe(value => {
this.msg = `Dragging the ${ value[1].innerText }!`;
});
this.dragula
<^>.drop<^>
.subscribe(value => {
this.msg = `Dropped the ${ value[1].innerText }!`;
setTimeout(() => {
this.msg = '';
}, 1000);
});
}
}
The value returned by both the drag and the drop event observables is an array containing the bag name (e.g.: <^>bag-items<^>), the dragged element and the container element (the <^><ul><^> element).
