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ngx-drag-to-select

3.1.1 • Public • Published

ngx-drag-to-select

travis styled with prettier npm npm License

A lightweight, fast, configurable and reactive drag-to-select component for Angular 6 and beyond

Demo

Live Demo

Playground

You can also fiddle with the library using StackBlitz. Credits for the template go to Bram Borggreve.

Features

  • Drag to Select
  • Shortcuts
  • Customizable 💅
  • Lightweight
  • Easy to use
  • Ready for AoT and SSR
  • Complies with the Angular Package Format
  • Includes FESM2015, FESM5, and UMD bundles 📦
  • It's fast 🏎
  • Mobile friendly 📱
  • Thoroughly tested 🚨

Examples

  • Desktop Example: Check out the AppComponent!
  • Mobile Example: There's a dedicated PhoneComponent component that uses all the tools and features from this library to implement a Google Inbox-like selection experience.

Table of contents

Installation

npm install ngx-drag-to-select

or

yarn add ngx-drag-to-select

Setup

Setting up ngx-drag-to-select is easy, and it only takes a few steps!

Adding the CSS

The first step is to add the CSS and for that you have two options. Either you use the default styles or you can import the ngx-drag-to-select sass package directly. The latter gives you the option to override variables and customize for instance the look and feel of the selection rectangle.

Using the default styles

Copy ngx-drag-to-select.css to your project and add it as a style tag to your index.html.

If you are using sass you can import the css as follows:

@import "~ngx-drag-to-select/ngx-drag-to-select.css";

If you are using the Angular CLI you can add it to your angular.json

"styles": [
  "styles.scss",
  "../node_modules/ngx-drag-to-select/ngx-drag-to-select.css"
]

Using the sass package

If you're using sass you can simply import the sass package. This allows you to override the default variables to customize the library to your needs.

@import "~ngx-drag-to-select/scss/ngx-drag-to-select";

Adding the module

In your AppModule import DragToSelectModule from ngx-drag-to-select and add it to the module imports:

import { DragToSelectModule } from 'ngx-drag-to-select';

@NgModule({
  imports: [
    DragToSelectModule.forRoot()
  ]
})
export class AppModule { }

That's it. You are now ready to use this library in your project. Make sure to call forRoot() only once in your AppModule and for feature modules you simply add the DragToSelectModule as is without calling forRoot().

Usage

Once you have installed the library and added the DragToSelectModule to your application you are ready to go.

Anywhere in your template add the dts-select-container component and wrap all items that you want to be selectable in this component.

Next, mark all selectable items with the dtsSelectItem directive. This connects each item with the container component.

Here's a complete example:

<dts-select-container #container="dts-select-container" [(selectedItems)]="selectedDocuments" (select)="someMethod($event)">
  <ul>
    <li [dtsSelectItem]="document" *ngFor="let document of documents">{{ document.name }}</li>
  </ul>
</dts-select-container>

Configuration Options

This section gives you an overview of things you can customize and configure.

Overriding sass variables

You can override the following variables:

Variable Type Default Description
$dts-primary Color #7ddafc Primary color
$select-box-color Color $dts-primary Color of the selection rectangle
$select-box-removing-color Color $dts-primary Color of the selection rectangle when removing items
$select-box-border-size Unit 2px Border size for the selection rectangle
$selected-item-border Boolean true Whether the selected item should get a border
$selected-item-border-color Color #d2d2d2 Border color of the selected item
$selected-item-border-size Unit 1px Border size of the selected item
$box-shadow Boolean true Whether the selected item should get a box shadow

If you wish to override one of these variables, make sure to do that before you import the sass package.

Example:

// Example for overriding the color of the selection retangle
$select-box-color: red;

@import "~ngx-drag-to-select/scss/ngx-drag-to-select";

Keep in mind that default styles are applied to all drag-to-select instances in your application. This means that if you override the color of the select box and set it so something like red then all instances render a red selection rectangle.

Configuring DragToSelectModule

This library allows to you override certain options, such as

selectedClass (String)

Class that is added to an item when it's selected. The default class is selected. Note that if you override this option, you'll lose the default styling and must take care of this yourself.

shortcuts (Object)

ngx-drag-to-select supports a hand full of shortcuts to make our live easier when selecting items.

Shortcut Default Description
disableSelection alt Disable selection mode to allow selecting text on the screen within the drag area
toggleSingleItem meta Add or remove single item to / from selection
addToSelection shift Add items to selection
removeFromSelection shift + meta Remove items from selection

You can override these options by passing a configuration object to forRoot().

Here's an example:

import { DragToSelectModule } from 'ngx-drag-to-select';

@NgModule({
  imports: [
    DragToSelectModule.forRoot({
      selectedClass: 'my-selected-item',
      shortcuts: {
        disableSelection: 'alt+meta'
      }
    })
  ]
})
export class AppModule { }

Note: If you override one of the shortscut you have to make sure they do not interfear with one another to ensure a smooth selecting experience.

Modifiers

When overriding the default shortcuts you can use the following modifier keys:

shift alt ctrl meta

When using meta, it will be substituted with ctrl (for Windows) and cmd (for Mac). This allows for cross-platform shortcuts.

Shortcut alternatives

You can also define alternative shortcuts. For that, simply chain the shortcuts with a comma. Here's an example:

shortcuts: {
  disableSelection: 'alt+meta,shift+alt'
}

API

ngx-drag-to-select comes with two main building blocks, a dts-select-container component and a dtsSelectItem directive.

dts-select-container

Inputs

Input Type Default Description
selectedItems Array / Collection of items that are currently selected
selectOnDrag Boolean true Whether items should be selected while dragging
disabled Boolean false Disable selection
disableDrag Boolean false Disable selection by dragging with the mouse. May be useful for mobile.
selectMode Boolean false If set to true, a toggle mode is activated similar to the toggleSingleItem shortcut. Useful for mobile.
custom Boolean false If set to true, all default styles for selected items will not be applied.
selectWithShortcut Boolean false If set to true, items can only be selected when single clicking and applying a keyboard shortcut

Here's an example of all inputs in action:

<dts-select-container
  [(selectedItems)]="selectedDocuments"
  [selectOnDrag]="true"
  [disabled]="false"
  [disableDrag]="true"
  [selectMode]="true"
  [custom]="true"
  [selectWithShortcut]="false">
  ...
</dts-select-container>
  • To get ahold of the selected items you can use a two-way data binding ([()]) aka banana-in-the-box syntax. This means that whenever the selection changes, your property is updated accordingly. It will always reflect the current selection.

  • Binding an expression to selectOnDrag will override the default value. When this option is set to false, it will increase the performance but you'll trade this for a slighly worse user experience.

Outputs

Input Payload Type Description
select Array Event that is fired when the selection changes. The payload ($event) will be the list of selected items.
itemSelected any Event that is fired when the item is selected. The payload ($event) will be the item's value
itemDeselected any Event that is fired when the item is deselected. The payload ($event) will be the item's value
selectionStarted None Event that is fired when the user starts selecting items.
selectionEnded Array Event that is fired when the user stops selecting items, typically by releasing the mouse button. The payload will be a list of all selected items

Example:

<dts-select-container (select)="someMethod($event)" (itemSelected)="itemSelected($event)" (itemDeselected)="itemDeselected($event)">
  ...
</dts-select-container>

Public Methods

Methods Description
selectAll() Select all items within the drag area
clearSelection() Clear current selection
update() Recalculate bounding box for the container and its children
selectItems(predicate) Select all items predicate returns truthy for
deselectItems(predicate) Deselect all items predicate returns truthy for
toggleItems(predicate) Toggle all items predicate returns truthy for

To access these methods on the container component you can either use the @ViewChild() decorator

import { Component, ViewChild } from '@angular/core';
import { SelectContainerComponent } from 'ngx-drag-to-select';

@Component({
  ...
})
export class AppComponent {
  @ViewChild(SelectContainerComponent) selectContainer: SelectContainerComponent;

  someMethod() {
    this.selectContainer.clearSelection();
  }
}

or use it within the template with a template reference variable

<button (click)="selectContainer.selectAll()">Select All</button>
<button (click)="selectContainer.clearSelection()">Clear Selection</button>

<dts-select-container #selectContainer="dts-select-container" [(selectedItems)]="selectedDocuments">
  ...
</dts-select-container>

What if I want to use the @ViewChild() decorator but have multiple instances of the dts-select-container in my template?

In that case I would recommend to add template reference variables to your select containers and query them one by one using the variable name.

Here's an example:

<dts-select-container #documents>
  ...
</dts-select-container>

...

<dts-select-container #images>
  ...
</dts-select-container>

In the component you can then query them one by one:

import { Component, ViewChild } from '@angular/core';
import { SelectContainerComponent } from 'ngx-drag-to-select';

@Component({
  ...
})
export class AppComponent {
  @ViewChild('documents') documentContainer: SelectContainerComponent;
  @ViewChild('images') imagesContainer: SelectContainerComponent;

  someMethod() {
    this.documentContainer.clearSelection();
  }

  someOtherMethod() {
    this.imagesContainer.selectAll();
  }
}

Select Box

Each instance of the dts-select-container renders its own select box. Based on the current selection mode, either adding or removing, the container adds corresponding css classes for more flexibility in styling. For adding items to the current selection, either in normal or extended mode, the select box gets a class of dts-adding. For removing items the class will be dts-removing. Both classes can be used to override the look and feel based on the selectio mode.

For instance, the color of the select box, when removing items, can be styled with a separate variable $select-box-removing-color. If the color should be the same for both adding and removing, the $dts-primary variable can be used.

selectItems(predicate)

Iterates over collection of SelectItemDirective's, selecting all items from that collection that meet the condition specified in the predicate function. The predicate is invoked with one argument item, which is equivalent to the value returned by SelectItemDirective.value.

Arguments

predicate ((item: T) => boolean): The function invoked per iteration.

Example

import { Component, ViewChild } from '@angular/core';
import { SelectContainerComponent } from 'ngx-drag-to-select';

@Component({
  ...
})
export class AppComponent {
  @ViewChild(SelectContainerComponent) selectContainer: SelectContainerComponent;

  someMethod() {
    this.selectContainer.selectItems(item => item.id === 1)
  }
}

deselectItems(predicate)

Iterates over collection of SelectItemDirective's, deselecting all items from that collection that meet the condition specified in the predicate function. The predicate is invoked with one argument item, which is equivalent to the value returned by SelectItemDirective.value.

Arguments

predicate ((item: T) => boolean): The function invoked per iteration.

Example

import { Component, ViewChild } from '@angular/core';
import { SelectContainerComponent } from 'ngx-drag-to-select';

@Component({
  ...
})
export class AppComponent {
  @ViewChild(SelectContainerComponent) selectContainer: SelectContainerComponent;

  someMethod() {
    this.selectContainer.deselectItems(item => item.id === 1)
  }
}

toggleItems(predicate)

Iterates over collection of SelectItemDirective's, toggling all items from that collection that meet the condition specified in the predicate function. The predicate is invoked with one argument item, which is equivalent to the value returned by SelectItemDirective.value.

Arguments

predicate ((item: T) => boolean): The function invoked per iteration.

Example

import { Component, ViewChild } from '@angular/core';
import { SelectContainerComponent } from 'ngx-drag-to-select';

@Component({
  ...
})
export class AppComponent {
  @ViewChild(SelectContainerComponent) selectContainer: SelectContainerComponent;

  someMethod() {
    this.selectContainer.toggleItems(item => [1, 2, 3].includes(item.id))
  }
}

dtsSelectItem

The dtsSelectItem directive is used to mark DOM elements as selectable items. It takes an input to control the value that is used when the item was selected. If the input is not specified, it will use the directive instance as a default value.

Inputs

Input Type Default Description
dtsSelectItem any Directive Instance Value that is used when the item is selected

Example:

<dts-select-container>
  <ul>
    <li [dtsSelectItem]="document" *ngFor="let document of documents">{{ document.name }}</li>
  </ul>
</dts-select-container>

Public Properties

Methods Type Description
selected Boolean Whether the item is selected or not

You can access this property in a similar why you access methods on the dts-select-container component using either a template reference variable or programmatically with the @ViewChild() decorator.

Example:

<dts-select-container>
  <ul>
    <li [dtsSelectItem]="document" #item *ngFor="let document of documents">
      {{ document.name }}
      <i class="fa fa-check" *ngIf="item.selected"></i>
    </li>
  </ul>
</dts-select-container>

FAQ

Is this library AoT and Universal compatible?

Yes.

Does this library work with Angular 5.x?

The latest version that supports Angular 5.x is 1.1.1. You can still install it via npm or yarn, e.g. npm install ngx-drag-to-select@1.1.1.

Note, that we try to always keep up with Angular's latest version, hence, older versions will not receive bug fixes nor new features.

Does this library work with mobile?

Yes. This library provides features that you need to implement a mobile version. Check out the Mobile Example, specifically the PhoneComponent component that uses all the tools and features from this library to implement a Google Inbox-like selection experience.

How do I deal with nested scrollable containers?

Suppose, we have the following markup:

<body>
  ...
  <div class="scrollable"><dts-select-container #container="dts-select-container"> ... </dts-select-container></div>
</body>

Here we have another wrapper elements that wraps the dts-select-container. This element is scrollable. The library does not account for any scrollable elements but the dts-select-container itself as well as the body. If you have other nested scrollable containers, and the rendering of the select-box seems to be off, you have to listen for the scroll event on your scrollable element and call update on the dts-select-container. This will make sure that whenever you scroll, the position of the select-container and its items on the screen are re-calculated.

Check out the solution to the problem:

<body>
  ...
  <div class="scrollable" (scroll)="container.update()">
    <dts-select-container #container="dts-select-container"> ... </dts-select-container>
  </div>
</body>

Here we listen for scroll on the div and call container.update() in case the event is fired.

In order not to kill the performance, because the scroll event is called many many times, you may want to throttle it to only call update every 16ms or so.

Want to contribute?

If you want to file a bug, contribute some code, or improve our documentation, read up on our contributing guidelines and code of conduct, and check out open issues.

For developers

If you want to set up ngx-drag-to-select on your machine for development, head over to our developers guide and follow the described instructions.

Versioning

ngx-drag-to-select will be maintained under the Semantic Versioning guidelines. Releases are numbered with the following format:

<MAJOR>.<MINOR>.<PATCH>
  1. MAJOR versions indicate incompatible API changes,
  2. MINOR versions add functionality in a backwards-compatible manner, and
  3. PATCH versions introduce backwards-compatible bug fixes.

For more information on SemVer, please visit http://semver.org.

Licence

MIT © Dominic Elm

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npm i ngx-drag-to-select

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461

version

3.1.1

license

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