ngx-scrollbar-indicator

Consider a scenario, where you have 100s of items, sorted alphabetically. Now, when user scrolls through the same, user doesn't know easily which character he/she has arrived, this is where ngx-scrollbar-indicator comes in picture. This will add an indicator to scrollbar, which will show first character of the item in view port.

What it does?
- Description
Examples
Installation
Usage
API
Styling
Development
Issues
Author
Credit
ToDos
Badges

What it does?

Description

Consider a scenario, where you have 100s of items, sorted alphabetically. Now, when user scrolls through the same, user doesn't know easily which character he/she has arrived, this is where ngx-scrollbar-indicator comes in picture. This will add an indicator to scrollbar, which will show first character of the item in view port. See screenshot below:

what it does gif

Examples

Stackblitz Basic, Styling
Github Pages Basic, Bootstrap

Installation

NPM

npm i ngx-scrollbar-indicator

Usage

Import NgxScrollbarIndicatorModule in your module

...
import { NgxScrollbarIndicatorModule } from 'ngx-scrollbar-indicator';
...
@NgModule({
  ...
  imports: [
    BrowserModule,
    ...,
    NgxScrollbarIndicatorModule
  ]
})
...

import in style.scss

@import "~ngx-scrollbar-indicator/assets/theme.scss";

In your template, wrap you element, in which you want indicator, like below :

<ngx-scrollbar-indicator #indicatorRef>
  <!-- Your element with *ngFor goes here. Do not forget to add attribute 'indicatorItem', which takes string from which first character will be visible in indicator. -->
</ngx-scrollbar-indicator>

API

API consists of Options, Properties, Methods and Observers.

Options ScrollbarIndicatorOptions

You can give options according to you need and modify the behavior. All options are optional. Below is full list of options :

Option	Type	Description
enable	boolean	Enable or disable indicator. Default : true
changeWhen deprecated	EChangeWhen (top/visible)	When the indicator should change the character? When character has reach top of container or as soon as it becomes visible in container. Default : EChangeWhen.top
containerHeight	number	height of the container, without this, scrolling won't work. Default : 500
theme	ETheme (circular/waterDrop/squareLike)	Visual theme of indicator, totally based on scss. Default : ETheme.waterDrop
position deprecated	EPosition (auto/top)	Position of indicator, whether to show on top or auto. Default : EPosition.auto
showWhen	EShowWhen (always/scroll)	When to show the indicator, always or onscroll/onhover. Default : EShowWhen.scroll

Properties

Name	Type	Description
all	ScrollbarIndicatorItemDirective[]	All Items Array
firsts	{ [x: string]: ScrollbarIndicatorItemDirective }	JSON Object with first item of each character
lasts	{ [x: string]: ScrollbarIndicatorItemDirective }	JSON Object with last item of each character

Methods

Name	Parameters	Returns	Description
showIndicator	- timer, this will help to maintain frequent calls to this function - duration (default 500), after which indicator will be hidden	Timer, which can be cleared if you are calling this function again within duration.	Ideally, you shouldn't call this. This will show the indicator. This will add 'show' class to the indicator. And After duration(default 500), if will remove the same. Calling this won't make any sense if showWhen is set to EShowWhen.always
goToLetter	- letter, Character to which viewport should be scrolled - position (default 'first') Element of that character group, first or last	offsetTop of element or -1 if error	Scroll to a specific letter, positioned first of last. Returns the offsetTop if element found, else -1. Works only in Non-IE Browsers.
startCalculation	none	void	Call this only if you are changing options in the run-time. This will calculate arrays and characters, based on options. This is called once after ngAfterContentInit hook.

Styling

Once you have imported theme.scss in style.scss, you will hae access to some variables. Be cautios while changing the same:

$indicator-background-color: #2196f3 !default;
$indicator-background-size: 46px !default;
$bubble-font-size: 16px !default;
$bubble-font-weight: 400 !default;
$indicator-font-color: #fff !default;
$indicator-margin-right: 8px !default;
$indicator-container-right: 105% !default;
$indicator-right: 105% !default;
$indicator-square-like-border-radius: 4px !default;

You can find the styling example on stackblitz.

Development

This project uses the Angular CLI for building the library.

$ ng build ngx-scrollbar-indicator

$ npm run build_lib

Issues

If you identify any errors in the library, or have an idea for an improvement, please open an issue.

Author

Dharmen Shah Github, Twitter

Credit

I would like to give few credits, as this is my first Angular Library.

Thanks
- Todd Palmer for great series at medium
- ng packagr for simplifying creating, packaging and publishing Angular Library process
Inspiration : Contacts app in Android.