orizens / ngx-infinite-scroll

Infinite Scroll Directive for Angular
https://www.npmjs.com/package/ngx-infinite-scroll
MIT License
1.25k stars 225 forks source link
angular angular-directives angular-library directive infinite-scroll scroll ui utility

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Angular Infinite Scroll

versions now follow Angular's version to easily reflect compatibility.
Meaning, for Angular 10, use ngx-infinite-scroll @ ^10.0.0

Angular - Older Versions Support

Starting Angular 6 and Above - ngx-infinite-scroll@THE_VERSION.0.0
For Angular 4 and Angular = ^5.5.6 - use version ngx-infinite-scroll@0.8.4
For Angular 5.x with rxjs =<5.5.2 - use version ngx-infinite-scroll@0.8.3
For Angular version <= 2.3.1, you can use npm i angular2-infinite-scroll (latest version is 0.3.42) - please notice the angular2-infinite-scroll package is deprecated

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Installation

npm install ngx-infinite-scroll --save

Supported API

Properties

@Input() Type Required Default Description
infiniteScrollDistance number optional 2 the bottom percentage point of the scroll nob relatively to the infinite-scroll container (i.e, 2 (2 * 10 = 20%) is event is triggered when 80% (100% - 20%) has been scrolled). if container.height is 900px, when the container is scrolled to or past the 720px, it will fire the scrolled event.
infiniteScrollUpDistance number optional 1.5 should get a number
infiniteScrollThrottle number optional 150 should get a number of milliseconds for throttle. The event will be triggered this many milliseconds after the user stops scrolling.
scrollWindow boolean optional true listens to the window scroll instead of the actual element scroll. this allows to invoke a callback function in the scope of the element while listenning to the window scroll.
immediateCheck boolean optional false invokes the handler immediately to check if a scroll event has been already triggred when the page has been loaded (i.e. - when you refresh a page that has been scrolled)
infiniteScrollDisabled boolean optional false doesn't invoke the handler if set to true
horizontal boolean optional false sets the scroll to listen for horizontal events
alwaysCallback boolean optional false instructs the scroller to always trigger events
infiniteScrollContainer string / HTMLElement optional null should get a html element or css selector for a scrollable element; window or current element will be used if this attribute is empty.
fromRoot boolean optional false if infiniteScrollContainer is set, this instructs the scroller to query the container selector from the root of the document object.

Events

@Output() Type Event Type Required Description
scrolled EventEmitter IInfiniteScrollEvent optional this will callback if the distance threshold has been reached on a scroll down.
scrolledUp EventEmitter IInfiniteScrollEvent optional this will callback if the distance threshold has been reached on a scroll up.

Behavior

By default, the directive listens to the window scroll event and invoked the callback.
To trigger the callback when the actual element is scrolled, these settings should be configured:

DEMO

Try the Demo in StackBlitz

Usage

In this example, the onScroll callback will be invoked when the window is scrolled down:

import { Component } from '@angular/core';
import { InfiniteScrollDirective } from 'ngx-infinite-scroll';

@Component({
  selector: 'app',
  template: `
    <div
      class="search-results"
      infiniteScroll
      [infiniteScrollDistance]="2"
      [infiniteScrollThrottle]="50"
      (scrolled)="onScroll()"
    ></div>
  `,
  standalone: true,
  imports: [InfiniteScrollDirective]
})
export class AppComponent {
  onScroll() {
    console.log('scrolled!!');
  }
}

in this example, whenever the "search-results" is scrolled, the callback will be invoked:

import { Component } from '@angular/core';
import { InfiniteScrollDirective } from 'ngx-infinite-scroll';

@Component({
  selector: 'app',
  styles: [
    `
      .search-results {
        height: 20rem;
        overflow: scroll;
      }
    `,
  ],
  template: `
    <div
      class="search-results"
      infiniteScroll
      [infiniteScrollDistance]="2"
      [infiniteScrollThrottle]="50"
      (scrolled)="onScroll()"
      [scrollWindow]="false"
    ></div>
  `,
  standalone: true,
  imports: [InfiniteScrollDirective]
})
export class AppComponent {
  onScroll() {
    console.log('scrolled!!');
  }
}

In this example, the onScrollDown callback will be invoked when the window is scrolled down and the onScrollUp callback will be invoked when the window is scrolled up:

import { Component } from '@angular/core';
import { InfiniteScroll } from 'ngx-infinite-scroll';

@Component({
  selector: 'app',
  directives: [InfiniteScroll],
  template: `
    <div
      class="search-results"
      infiniteScroll
      [infiniteScrollDistance]="2"
      [infiniteScrollUpDistance]="1.5"
      [infiniteScrollThrottle]="50"
      (scrolled)="onScrollDown()"
      (scrolledUp)="onScrollUp()"
    ></div>
  `,
  standalone: true,
})
export class AppComponent {
  onScrollDown() {
    console.log('scrolled down!!');
  }

  onScrollUp() {
    console.log('scrolled up!!');
  }
}

In this example, the infiniteScrollContainer attribute is used to point directive to the scrollable container using a css selector. fromRoot is used to determine whether the scroll container has to be searched within the whole document ([fromRoot]="true") or just inside the infiniteScroll directive ([fromRoot]="false", default option).

import { Component } from '@angular/core';
import { InfiniteScrollDirective } from 'ngx-infinite-scroll';

@Component({
  selector: 'app',
  styles: [
    `
      .main-panel {
        height: 100px;
        overflow-y: scroll;
      }
    `,
  ],
  template: `
    <div class="main-panel">
      <div
        infiniteScroll
        [infiniteScrollDistance]="2"
        [infiniteScrollThrottle]="50"
        [infiniteScrollContainer]="selector"
        [fromRoot]="true"
        (scrolled)="onScroll()"
      ></div>
    </div>
  `,
  standalone: true,
  imports: [InfiniteScrollDirective]
})
export class AppComponent {
  selector: string = '.main-panel';

  onScroll() {
    console.log('scrolled!!');
  }
}

It is also possible to use infiniteScrollContainer without additional variable by using single quotes inside double quotes:

[infiniteScrollContainer]="'.main-panel'"

Showcase Examples

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