angular-infinite-list

A short and powerful infinite scroll list library for angular, with zero dependencies

Description

This library is transplanted from react-tiny-virtual-list and react-virtualized.

Check out the demo for some examples.

Programming language: TypeScript

License: MIT License

Tags: Scroll     Angular     Angular5     Angular-scroll     Infinite List    

README

A short and powerful infinite scroll list library for angular, with zero dependencies 💪

• Tiny & dependency free – Only 3kb gzipped
• Render millions of items, without breaking a sweat
• Scroll to index or set the initial scroll offset
• Supports fixed or variable heights/widths
• Vertical or Horizontal lists

This library is transplanted from react-tiny-virtual-list and react-virtualized.

Check out the demo for some examples.

Getting Started

Using npm:

npm install angular-infinite-list --save

Import angular Infinite list module into your app module

import { InfiniteListModule } from 'angular-infinite-list';

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    InfiniteListModule,
    ...

Wrap Infinite list tag around list items

<infinitelist
    style="width:100%"
    [width]='"100%"' 
    [height]='500' 
    [data]='data' 
    [itemSize]='50' 
    (update)='event = $event'>
        <div *ngFor="let item of event?.items; let i=index;" [ngStyle]="event.getStyle(i)">
            item{{event.start + i}} : {{item|json}}
        </div>
</infinitelist>

or directive usage
<div infinitelist [width]='"100%"' ...</div>

Higher performance usage

Because in the angular all the asynchronous operation will cause change detection.High-frequency operations such as the scroll event can cause significant performance losses.

So in some high-precision scenes, we can use rxjs Observable to solve. About angular asynchronous, change detection checks and zone.js. You can view zone.js and change detection

set @Input [useob]='true' and use ChangeDetectorRef

You can switch to the Observable mode. of course, if your scene on the efficiency requirements are not high can not do so.

demo.component.html

<infinitelist
    [width]='"100%"' 
    [height]='500' 
    [data]='data' 
    [itemSize]='150' 
    [useob]='true'
    (update)='update($event)'>
        <div class="li-con" *ngFor="let item of event?.items; let i=index;" [ngStyle]="event.getStyle(i)">
            item{{event.start + i}}
        </div>
</infinitelist>

demo.component.ts

Notice! useob mode update trigger once and otherwise it will trigger multiple times

event: ILEvent;
constructor(private cdRef: ChangeDetectorRef) { }

//Notice! useob mode update trigger once and otherwise it will trigger multiple times
update($event: Subject<any>) {
    $event.subscribe(x => {
        this.event = x;
        this.cdRef.detectChanges();
    });
}

view demo code

Prop Types

Property	Type	Required?	Description
width	Number or String*	✓	Width of List. This property will determine the number of rendered items when scrollDirection is 'horizontal'.
height	Number or String*	✓	Height of List. This property will determine the number of rendered items when scrollDirection is 'vertical'.
data	any[]	✓	The data that builds the templates within the Infinite scroll.
itemSize		✓	Either a fixed height/width (depending on the scrollDirection), an array containing the heights of all the items in your list, or a function that returns the height of an item given its index: (index: number): number
scrollDirection	String		Whether the list should scroll vertically or horizontally. One of 'vertical' (default) or 'horizontal'.
scrollOffset	Number		Can be used to control the scroll offset; Also useful for setting an initial scroll offset
scrollToIndex	Number		Item index to scroll to (by forcefully scrolling if necessary)
scrollToAlignment	String		Used in combination with scrollToIndex, this prop controls the alignment of the scrolled to item. One of: 'start', 'center', 'end' or 'auto'. Use 'start' to always align items to the top of the container and 'end' to align them bottom. Use 'center' to align them in the middle of the container. 'auto' scrolls the least amount possible to ensure that the specified scrollToIndex item is fully visible.
overscanCount	Number		Number of extra buffer items to render above/below the visible items. Tweaking this can help reduce scroll flickering on certain browsers/devices.
estimatedItemSize	Number		Used to estimate the total size of the list before all of its items have actually been measured. The estimated total height is progressively adjusted as items are rendered.
update	Output		This event is fired every time when dom scroll. The event sent by the parameter is a ILEvent object.

* Width may only be a string when scrollDirection is 'vertical'. Similarly, Height may only be a string if scrollDirection is 'horizontal'

The IILEvent interface

export interface IILEvent {
    items: any[],
    offset: number,
    getStyle(index: number): any,
    data?: any[],
    start?: number,
    stop?: number
}

Reporting Issues

Found an issue? Please report it along with any relevant details to reproduce it.

Acknowledgments

This library is transplanted from react-tiny-virtual-list and react-virtualized. Thanks for the great works of author Claudéric Demers ❤️

License

is available under the MIT License.