ng-hotkeys

ng-hotkeys

An Angular module that provides a declarative API using components/directive to manage Keyboard shortcuts in scalable way.

See demo here:
demo

Compatible with Angular 14+

• Install

• Setup

• Demo

• Usage

  • Combinations
  • Sequences
  • Components
    • Keyboardshortcuts
    • HelpScreen
  • Directive
    • NgHotkeysDirective
  • Service
    • NgHotkeysHelpService
    • NgHotkeysSelectService

• API

  • Types
    • AllowIn
    • Shortcut
    • ShortcutInput
    • ShortcutEventOutput

• Building

• Publishing

• License

Install:

NPM

Angular latest

npm install --save ng-hotkeys

Yarn

Angular latest

yarn add ng-hotkeys

Setup:

import { HotKeysModule }     from 'ng-hotkeys';  
  
@NgModule({  
    declarations: [  
    ],  
    imports: [  
        BrowserModule,  
        HotKeysModule.forRoot()  
    ],  
    bootstrap: [AppComponent]  
})  
export class AppModule {  
}  

Usage:

Combinations

key combinations are used with meta keys like control, shift, command, etc... and are defined using plus(+) sign as a separator. there can be multiple combinations for the same command, so either of the key combination will trigger the callback. Since combinations uses the plus sign as a seperator, if you want to bind to the actual + charachater, you will need to use "plus" instead.

Examples:

   [
       {
            key: ["cmd + a"],
            command: (output: ShortcutEventOutput) => console.log("command + a", output),
        },
        {
            key: "ctrl + a",
            preventDefault: true,
            command: (output: ShortcutEventOutput) => console.log("control + a", output),
            
        },
        {
            key: "ctrl + plus",
            preventDefault: true,
            command: (output: ShortcutEventOutput) => console.log("control + plus key", output),
        }
    ]

Sequences

Sequences can be used to support gmail like actions where you click "g" then "a", or "g" then "o" to perform certain actions.

Important note

The library can get very confused if you have a single key handler that uses the same key that a sequence starts with. This is because it can't tell if you are starting the sequence or if you are pressing that key on its own.

To counter this, there is a 500ms delay(only when single key is used in the beginning of another sequence, so it won't affect performance) . This gives the library time to wait for a more complete sequence, otherwise the single sequence will be triggered.

for example: binding both "? a" and "?", then clicking "?" will trigger the "?" callback, but only after 500ms delay. However, in all other cases there's no delay in execution of the callback (unless debounceTime is provided)

Examples:

This library supports gmail style sequences:

   [{
        key: ["g a"],
        command: (output: ShortcutEventOutput) => console.log("? a", output),
    }]

konami code:

    [{
         key: ["up up down down left right left right b a enter"],
         label: "Sequences",
         description: "Konami code!",
         command: (output: ShortcutEventOutput) => console.log("Konami code!!!", output),
    }]

Sequences can be used inside components or directives and are declared without the plus(+) sign, for example: key: ["a b c"] will require clicking, a, then b, then c.

Components:

ng-hotkeys

Component that can be used across the app to bind to various shortcuts

Inputs:

Name	Type	Default	Description
shortcuts	ShortcutInput / ShortcutInput[]	[]	List of shortcut inputs types see types
disabled	boolean	false	disable the shortcuts for the component

Methods:

Name	Input	Return	Description
select	string - key to listen to events (example: 'cmd + e')	Observable<ShortcutEventOutput>	Listen to specific key events (will only work for registered keys)

  
import { AfterViewInit, Component, ElementRef, OnInit, ViewChild } from "@angular/core";  
import { ShortcutInput, ShortcutEventOutput, NgHotkeysComponent } from "ng-hotkeys";  
  
@Component({  
    selector: 'demo-component',  
    template: "<ng-hotkeys [shortcuts]="shortcuts"></ng-hotkeys>"  
})  
export class DemoComponent implements AfterViewInit {  
  
    shortcuts: ShortcutInput[] = [];  
    @ViewChild('input') input: ElementRef;  
  
    ngAfterViewInit(): void {  
        this.shortcuts.push(  
            {  
                key: "ctrl + t",  
                preventDefault: true,  
                allowIn: [AllowIn.Textarea, AllowIn.Input],  
                command: e => console.log("clicked " , e.key)  
            },
           {
                key: ["? a"],
                label: "Sequences",
                description: "Sequence ? and a",
                command: (output: ShortcutEventOutput) => console.log("? a", output),
                preventDefault: true
            },            
            {
                key: ["up up down down left right left right b a enter"],
                label: "Sequences",
                description: "Konami code!",
                command: (output: ShortcutEventOutput) => console.log("Konami code!!!", output),
            },
            {  
                key: "cmd + shift + f",  
                command: (output: ShortcutEventOutput) => console.log(output),  
                preventDefault: true,  
                throttleTime: 250,  
                target: this.input.nativeElement  
            },  
            {  
                key: ["cmd + =", "cmd + z"],  
                command: (output: ShortcutEventOutput) => console.log(output),  
                preventDefault: true  
            },  
            {  
                key: "cmd + f",  
                command: (output: ShortcutEventOutput) => console.log(output),  
                preventDefault: true  
            }  
        );  
  
        this.keyboard.select("cmd + f").subscribe(e => console.log(e));  
    }  
  
    @ViewChild(NgHotkeysComponent) private keyboard: NgHotkeysComponent;  
  
}  

ng-hotkeys-help

• Make sure to install @angular/animations ( npm install --save @angular/animations or yarn add @angular/animations
• Add BrowserAnimationsModule to your app.module imports

Can be used to show an help screen ( will be attached to body and be shown as a modal)

Should be placed in the root of your app, preferably in app.component.html

Inputs

Name	Type	default	description
key	string	none	The key to show/hide the help modal
keyDescription	string	none	Description to show in the menu shortcut list for the toggle shortcut
keyLabel	string	none	Label that can be used to group shortcuts together in the help menu
closeKey	string	none	Close key to be used to close the modal
closeKeyDescription	string	none	Description to show in the menu shortcut list for closing the modal shortcut
closeKeyLabel	string	none	Label that can be used to group shortcuts together in the help menu
title	string	"Keyboard shortcuts"	The title of the help screen
emptyMessage	string	"No shortcuts available"	What message to show when no commands are registered when help modal is opened.
disableScrolling	boolean	true	Whether to disable body scrolling when modal help screen is opened.

Methods:

Name	Input	Return	Description
hide	void	NgHotkeysHelpComponent	Programmatically hide the modal
reveal	void	NgHotkeysHelpComponent	Programmatically hide the modal
visible	void	boolean	Check whether the modal is visible or not.
toggle	void	NgHotkeysHelpComponent	Programmatically toggle the modal visibility

Methods:

Name	Input	Return	Description
select	string - key to listen to events (example: 'cmd + e')	Observable<ShortcutEventOutput>	Listen to specific key events (will only work for registered keys)

app.component.ts

import { Component } from "@angular/core";  
  
@Component({  
  selector: "app-root",  
  template: "./app.component.html",  
  styleUrls: ["./app.component.css"]  
})  
export class AppComponent {  
  title = "Hello";  
}  
  

app.component.html

<div style="text-align:center">  
   <h1>  
      Welcome to {{ title }}!  
   </h1>  
   <ng-hotkeys-help [key]="'f1'" [closeKey]="'escape'" [title]="'Help'"></ng-hotkeys-help>  
</div>  
  

Directive

NgHotkeysDirective

Directive can only be used for focusable elements, such as textarea, select, input, etc...

Important:

The shortcut then will only be active while the element is in focus.

Inputs

Name	Type	default	description
ngHotKeys	Shortcut / Shortcut	[]	List of shortcuts see types
disabled	boolean	false	disable the shortcuts for the directive
disableScrolling	boolean	true	disable body scrolling while modal is open

Example

import { AfterViewInit, Component, ElementRef, OnInit, ViewChild } from "@angular/core";  
import { ShortcutInput, ShortcutEventOutput, NgHotkeysComponent } from "ng-hotkeys";  
  
@Component({  
    selector: 'demo-component',  
    template: "<input [ngHotKeys]="shortcuts" />"  
})  
export class DemoComponent implements AfterViewInit {  
  
    shortcuts: ShortcutInput[] = [];  
    @ViewChild('input') input: ElementRef;  
  
    ngAfterViewInit(): void {  
        this.shortcuts.push({  
            key: "cmd + e",  
            label: "test",  
            description: "hello world",  
            command: () => console.log('directive cmd + e'),  
            preventDefault: true  
        });  
  
        this.keyboard.select("cmd + f").subscribe(e => console.log(e));  
    }  
  
    @ViewChild(NgHotkeysComponent) private keyboard: NgHotkeysComponent;  
  
}  

Service

NgHotkeysHelpService

Singleton service that can be used to render a custom help screen. (used to build the Built in help component)
Provides access to all registered shortcuts in the app using Observable that updates on shortcuts changes.
Since shortcuts can be added or removed during the lifecycle of the app, an observable data structure needed to be used.

properties	type	description
shortcuts$	Observable<{ key: string, label: string, description: string }[]>	Array of registered shortcuts across the whole app

NgHotkeysSelectService

A singleton service that can be used globally to listen to any registered shortcut:

Name	Input	Return	Description
select	string - key to listen to events (example: 'cmd + e')	Observable<ShortcutEventOutput>	Listen to specific key events (will only work for registered keys)

API:

Types:

AllowIn

export enum AllowIn {  
    Textarea = 'TEXTAREA',  
    Input = 'INPUT',  
    Select = "SELECT"  
}  

Shortcut

Used for Directive input

export interface Shortcut {  
  
    key: string | string[];  
  
    /**  
     * callback to be called when shortcut is pressed.  
     * @param event - the event out  
     */  
    command(event: ShortcutEventOutput): any;  
  
    /**  
     * Description for the command can be used for rendering help menu.  
     */  
    description?: string;  
  
    /**  
     * How much time to throttle in ms.  
     */  
    throttleTime?: number;  
  
    /**  
     * Label, can be used for grouping commands.  
     */  
    label?: string;  
  
    /**  
     * Prevent browser default, default: false  
     */  
    preventDefault?: boolean;  
}  

ShortcutInput

Used for the component as input.

export interface ShortcutInput extends Shortcut {  
    /**  
     * textarea, select and input are ignored by default, this is used to override  
     * this behavior.  
     * allow in node names, accepts: ["TEXTAREA", "SELECT", "INPUT]  
     */  
    allowIn?: AllowIn[];  
    /**  
     * Only trigger the command when the target is in focus.  
     */  
    target?: HTMLElement;  
}  

ShortcutEventOutput

type = ShortcutEventOutput {  
    event: KeyboardEvent;  
    key: string | string[];  
}  
  

Building

npm run build-lib

Publishing

• npm run build-lib
• npm publish dist/ng-hotkeys

License

This project is licensed under the MIT License - see the LICENSE file for details