/lenis

How smooth scroll should be

Primary LanguageJavaScript

LENIS

npm version size

Introduction

This is our take on smooth scroll, lightweight, hard-working, smooth as butter scroll. See Demo.


Installation

using a package manager:

$ npm i @studio-freight/lenis
import Lenis from '@studio-freight/lenis'

using scripts:

<script src="https://cdn.jsdelivr.net/gh/studio-freight/lenis@1.0.26/bundled/lenis.min.js"></script>

Setup

Basic setup:

const lenis = new Lenis()

lenis.on('scroll', (e) => {
  console.log(e)
})

function raf(time) {
  lenis.raf(time)
  requestAnimationFrame(raf)
}

requestAnimationFrame(raf)

Instance settings

Option Type Default Description
wrapper HTMLElement, Window window The element that will be used as the scroll container
content HTMLElement document.documentElement The element that contains the content that will be scrolled, usually wrapper's direct child
eventsTarget HTMLElement, Window wrapper The element that will listen to wheel and touch events
lerp number 0.1 Linear interpolation (lerp) intensity (between 0 and 1)
duration number 1.2 The duration of scroll animation (in seconds). Useless if lerp defined
easing function (t) => Math.min(1, 1.001 - Math.pow(2, -10 * t)) The easing function to use for the scroll animation, our default is custom but you can pick one from Easings.net. Useless if lerp defined
orientation string vertical The orientation of the scrolling. Can be vertical or horizontal
gestureOrientation string vertical The orientation of the gestures. Can be vertical, horizontal or both
smoothWheel boolean false Whether or not to enable smooth scrolling for mouse wheel events
smoothTouch boolean false Whether or not to enable smooth scrolling for touch events.
syncTouch boolean false Mimic touch device scroll while allowing scroll sync (can be unstable on iOS<16)
syncTouchLerp number 0.1 Lerp applied during syncTouch inertia
touchInertiaMultiplier number 35 Manage the the strength of syncTouch inertia
wheelMultiplier number 1 The multiplier to use for mouse wheel events
touchMultiplier number 2 The multiplier to use for touch events
normalizeWheel boolean false Normalize wheel inputs across browsers (not reliable atm)
infinite boolean false Enable infinite scrolling!
autoResize boolean true Resize instance automatically based on ResizeObserver. If false you must resize manually using .resize()

Instance Props

Property Type Description
animatedScroll number Current scroll value
dimensions object Dimensions instance
direction number 1: scrolling up, -1: scrolling down
emitter object Emitter instance
options object Instance options
targetScroll number Target scroll value
time number Time elapsed since instance creation
actualScroll number Current scroll value registered by the browser
velocity number Current scroll velocity
isHorizontal (getter) boolean Whether or not the instance is horizontal
isScrolling (getter) boolean Whether or not the scroll is being animated
isSmooth (getter) boolean Whether or not the scroll is animated
isStopped (getter) boolean Whether or not the user should be able to scroll
limit (getter) number Maximum scroll value
progress (getter) number Scroll progress from 0 to 1
rootElement (getter) HTMLElement Element on which Lenis is instanced
scroll (getter) number Current scroll value (handles infinite scroll if activated)
className (getter) string rootElement className

Instance Methods

Method Description Arguments
raf(time) Must be called every frame for internal usage. time: in ms
scrollTo(target, options) Scroll to target. target: goal to reach
  • number: value to scroll in pixels
  • string: CSS selector or keyword (top, left, start, bottom, right, end)
  • HTMLElement: DOM element
options
  • offset(number): equivalent to scroll-padding-top
  • lerp(number): animation lerp intensity
  • duration(number): animation duration (in seconds)
  • easing(function): animation easing
  • immediate(boolean): ignore duration, easing and lerp
  • lock(boolean): whether or not to prevent the user from scrolling until the target is reached
  • force(boolean): reach target even if instance is stopped
  • onComplete(function): called when the target is reached
on(id, function) id can be any of the following instance events to listen.
stop() Pauses the scroll
start() Resumes the scroll
resize() Compute internal sizes, it has to be used if autoResize option is false.
destroy() Destroys the instance and removes all events.

Instance Events

Event Callback Arguments
scroll Lenis instance

Recommended CSS

html.lenis {
  height: auto;
}

.lenis.lenis-smooth {
  scroll-behavior: auto;
}

.lenis.lenis-smooth [data-lenis-prevent] {
  overscroll-behavior: contain;
}

.lenis.lenis-stopped {
  overflow: hidden;
}

.lenis.lenis-scrolling iframe {
  pointer-events: none;
}

Considerations

Nested scroll

<div data-lenis-prevent>scroll content</div>

<div data-lenis-prevent-wheel>scroll content</div>

<div data-lenis-prevent-touch>scroll content</div>

Anchor links

<a href="#anchor" onclick="lenis.scrollTo('#anchor')">scroll to anchor</a>

GSAP ScrollTrigger integration

const lenis = new Lenis()

lenis.on('scroll', ScrollTrigger.update)

gsap.ticker.add((time)=>{
  lenis.raf(time * 1000)
})

gsap.ticker.lagSmoothing(0)

Limitations

  • no support for CSS scroll-snap
  • capped to 60fps on Safari (source)
  • smooth scroll will stop working over iframe since they don't forward wheel events
  • position fixed seems to lag on MacOS Safari pre-M1 (source)

Tutorials


Plugins


Lenis in use


Authors

This set of hooks is curated and maintained by the Studio Freight Darkroom team:


License

The MIT License.