React Scroll Parallax
Provides a React component and single passive scroll listener to add vertical scrolling based offsets to elements based on their position in the viewport. Works with universal (server-side rendered) React apps.
View on NPM
Examples
🔗 CodePen Parallax
🔗 Example Site
🔗 Parallax Testing
Install
npm i react-scroll-parallax --save
Usage
Wrap your component tree that will contain <Parallax />
components with the <ParallaxProvider />
. For example:
...
import { ParallaxProvider } from 'react-scroll-parallax';
class App extends Component {
render() {
return (
<ParallaxProvider>
<StuffWithParallax />
</ParallaxProvider>
);
}
}
Import the Parallax
component...
import { Parallax } from 'react-scroll-parallax';
... then use it like so:
<Parallax
className="custom-class"
offsetYMax={20}
offsetYMin={-20}
slowerScrollRate
tag="figure"
>
<img src="/image" />
</Parallax>
NOTE: Scroll state and positions of elements on the page are cached for performance reasons. This means that if the page height changes (perhaps from images loading) after <Parallax />
components are mounted the controller won't properly determine when the elements are in view. To correct this you can call the parallaxController.update()
method from any child component of the <ParallaxProvider />
via context
. More details on how here: Parallax Controller Context.
Parallax Component Props
The following are all props that can be passed to the React <Parallax />
component:
className
Optionally pass additional class names to be added to the outer parallax element.
disabled
- type:
Boolean
- default:
false
Determines if the component will have parallax offsets applied. If true
parallax styles are completely removed from the element and it is no longer updated.
offsetXMax
- type:
Number
or String
- default:
0
Maximum x offset in %
or px
. If no unit is passed percent is assumed. Percent is based on the elements width.
offsetXMin
- type:
Number
or String
- default:
0
Minimum x offset in %
or px
. If no unit is passed percent is assumed. Percent is based on the elements width.
offsetYMax
- type:
Number
or String
- default:
0
Maximum y offset in %
or px
. If no unit is passed percent is assumed. Percent is based on the elements height.
offsetYMin
- type:
Number
or String
- default:
0
Minimum y offset in %
or px
. If no unit is passed percent is assumed. Percent is based on the elements height.
slowerScrollRate
- type:
Boolean
- default
false
Determines whether the scroll rate of the parallax component will move faster or slower than the default rate of scroll.
tag
Optionally pass a tag name to be applied to the outer most parallax element. For example: <Parallax tag="figure" />
.
Parallax Controller Context
Access the Parallax Controller via React context in any components rendered within a <ParallaxProvider />
by defining the contextTypes
like so:
class Foo extends Component {
static contextTypes = {
parallaxController: PropTypes.object.isRequired,
};
doSomething() {
}
...
or for stateless functional components like:
const Bar = (props, context) => (
...
);
Bar.contextTypes = {
parallaxController: PropTypes.object.isRequired,
};
Available Methods
Access the following methods on parallaxController
via context:
update()
Updates all cached attributes for parallax elements then updates their positions.
destroy()
Removes window scroll and resize listeners then resets all styles applied to parallax elements.
Browser Support
React scroll parallax should support the last two versions of all major browsers and has been tested on desktop Chrome, Firefox, Safari and Edge, as well as the following: iOS 9, iOS 10, Android 4 and IE11. If you encounter any errors for browsers that should be supported please post an issue.
Optimizations to Reduce Jank
React Scroll Parallax uses a single passive scroll listener (dependent on browser support) with the minimal amount of work done on the scroll event to prevent jank (calculations that cause layout, reflow and paint are cached initially and only updated when layout changes). Request animation frame is then used to decouple the scroll handler and further reduce jank. All offsets are applied with 3D transforms to utilize the GPU and prevent paints. If you have ideas to further optimize scrolling please PR or post an issue.
PSA
It's 2017 and you probably shouldn't be building parallax sites—but if you do (like I did) and you use this package try and use it responsibly. Keeping images small and optimized, reducing the number of moving elements in view and on the page, and disabling scroll effects on mobile devices should keep scrolling smooth.