ngx-page-scroll
v13.0.0
Published
Convenience directive for animated scrolling functionality for angular written in pure typescript
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ngx-page-scroll
Animated scrolling functionality for angular written in pure typescript with no additional dependencies
Features
- flexible: trigger scroll animations after component load, server response, etc.
- easy-to-use directive: scroll to an element referenced in the href-attribute
(
href="#mytarget
) just by addingpageScroll
directive - customizable: adjust duration, offset or whether scrolling stops if the user interrupts (read more)
- use custom easing functions to calculate the scroll position over time
- works across routes (scrolls to target element as soon as the routing has finished) and in both directions (horizontal/vertical)
Table of contents
Version compatibility
Install later versions in case your app is not running the very latest angular version.
| ngx-page-scroll/ngx-page-scroll-core version | compatible angular version | Documentation | | -------------------------------------------- | -------------------------- | -------------------------------------------------------------------------- | | v12.x | v17 | README | | v11.x | v16 | README | | v10.x | v15 | README| | v9.x | v14 | README | | v8.x | v13 | README | | v7.x | v12, v11, v10, v9, v8 | README | | v6.x | v8, v7 | README | | v5.x | v6 | README | | v4.x | v5, v4 | README |
Service
Setup
First you need to install the core npm module:
npm install ngx-page-scroll-core --save
Then add the NgxPageScrollModule
to the imports array of your application module:
import { NgxPageScrollCoreModule } from 'ngx-page-scroll-core';
@NgModule({
imports: [
/* Other imports here */
NgxPageScrollCoreModule
]
})
export class AppModule {
}
Usage
Using the PageScrollService#scroll
method you may trigger scroll animations. Provide an options object that provides a reference to the document and the scroll target. Additional properties are optional.
import { Inject } from '@angular/core';
import { DOCUMENT } from '@angular/common';
import { PageScrollService } from 'ngx-page-scroll-core';
export class MyComponent {
constructor(private pageScrollService: PageScrollService, @Inject(DOCUMENT) private document: any) {
}
ngOnInit(): void {
this.pageScrollService.scroll({
document: this.document,
scrollTarget: '.theEnd',
});
}
}
Note: The scroll()
method is a shorthand from creating a PageScrollInstance
(an object encapsulating all information
relevant for performing a scroll animation) using PageScrollService#create
and starting it using
the PageScrollService#start
method.
Configuration
When importing the PageScrollCoreModule
one can provide option overrides:
imports: [
...
NgxPageScrollCoreModule.forRoot({duration: 2500, easingLogic: ...}),
]
Check the PageScrollConfig
interface
for possible options and their impact. The default values may be found in the defaultPageScrollConfig
object.
Directive
For ease of use a directive pageScroll
exists, which allows you to quickly add scroll animations to your angular app by
adding a property to your existing HTML a-tags. It can also work cross-routes, meaning it will start the scroll animation
after the target route has been loaded.
It utilizes the ngx-page-scroll-core module for that, thus requires it as a peer dependency.
Setup
First you need to install the directive npm module:
npm install ngx-page-scroll --save
Then add the NgxPageScrollModule
to the imports array of your application module:
import { NgxPageScrollModule } from 'ngx-page-scroll';
@NgModule({
imports: [
/* Other imports here */
NgxPageScrollModule
]
})
export class AppModule {
}
Usage
In your template you may add the pageScroll
attribute to elements with an href
attribute pointing towards an id on
the same page (e.g. #theId
). The onClick
event will be interrupted and the scroll animation starts.
Alternatively you may set the optional pageScrollTarget
property to a valid css selector to specify the
target element to scroll to.
@Component({
...
template: `...
<a pageScroll href="#awesomePart">Take me to the awesomeness</a>
<!-- Further content here -->
<h2 id="awesomePart">This is where the awesome happens</h2>
...`,
})
export class MyComponent {
}
Directive API
Additional attributes may be set on an DOM element using the pageScroll
directive for customization.
They take precedence over the default settings specified in PageScrollConfig
class. Thereby it is
possible to have all page scroll-animations last e.g. 2 seconds, but a specific one should be performed with a custom easing function and a duration
of only 1 second.
PageScroll properties
| Attribute | Type | Default | Description |
| ------------------------- | ----------- | ------------ |-------------- |
| pageScroll
| | | Attribute adding scroll-animation behavior when the click
-event happens on the element. |
| pageScrollTarget
| string | | Optional attribute to set the element that should be scrolled to. Takes precedence over the ´href´-value |
| pageScrollHorizontal
| boolean | false | Whether the scroll should happen in vertical direction (false
, default) or horizontal (true
). |
| pageScrollOffset
| number | 0 | Pixels to offset from the top of the element when scrolling to (positive value = scrolling will stop given pixels atop the target element). |
| pageScrollDuration
| number | 1250 | Duration in milliseconds the whole scroll-animation should last. |
| pageScrollSpeed
| number | - | Speed in Pixel/Second the animation should take. Only applied if no duration is set. |
| pageScrollInView
| boolean | true | Whether the scroll animation should happen even when the scroll target is already inside the view port (true
). Set to false
to skip scroll animation if target is already in view. |
| pageScrollInterruptible
| boolean | true | Whether the scroll animation should stop if the user interferes with it (true
) or not (false
). |
| pageScrollAdjustHash
| boolean | false | Whether the routes hash/fragment should be updated to reflect to section that has been scrolled to |
| pageScrollEasing
| EasingLogic | linearEasing | Easing method to be used while calculating the scroll position over time (default is linear easing). |
PageScroll events
| Event | Type | Description |
| --------------------- | ------- | ------------- |
| pageScrollFinish
| boolean | Fired when the scroll-animation stops. Emits a boolean value which indicates whether the scroll animation finished successfully and reached its target (true
) or not (false
). Possible reasons for false: target not found or interrupted due to another scroll animation starting or user interaction. |
Example
The following example will check whether the route Home is currently loaded. If this is true, the scroll-animation will be performed with the default properties. If a different route is loaded, a subscription for route changes will be made and the scroll-animation will be performed as soon as the new route is loaded.
<a pageScroll [routerLink]="['Home']" href="#myanchor">Go there</a>
Overriding all possible properties. doSmth()
and myEasing
are
defined in the component
<a pageScroll [pageScrollOffset]="0" [pageScrollDuration]="2000" [pageScrollEasing]="myEasing" [pageScrollInterruptible]="false" (pageScrollFinish)="doSmth($event)" href="#theanchor">Visit</a>
public myEasing: EasingLogic = (t: number, b: number, c: number, d: number): number => {
// easeInOutExpo easing
if (t === 0) {
return b;
}
if (t === d) {
return b + c;
}
if ((t /= d / 2) < 1) {
return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
}
return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
}
doSmth(reachedTarget: boolean): void {
if (reachedTarget) {
console.log('Yeah, we reached our destination');
} else {
console.log('Ohoh, something interrupted us');
}
}
FAQ and common problems
Please have a look at the wiki section of the GitHub repo at https://github.com/Nolanus/ngx-page-scroll/wiki/FAQ for frequent questions and problems.