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| import React from 'react';
import _ from 'lodash';
import { lucidClassNames } from '../../util/style-helpers';
import { createClass, omitProps } from '../../util/component-types';
import { getAbsoluteBoundingClientRect } from '../../util/dom-helpers';
const cx = lucidClassNames.bind('&-StickySection');
const {
node,
number,
object,
string,
} = React.PropTypes;
/**
* {"categories": ["helpers"]}
*
* `StickySection` can be wrapped around any content to make it _stick_ to the
* top edge of the screen when a user scrolls beyond its initial location.
*/
const StickySection = createClass({
displayName: 'StickySection',
propTypes: {
/**
* any valid React children
*/
children: node,
/**
* Appended to the component-specific class names set on the root element.
*/
className: string,
/**
* Styles that are passed through to the root container.
*/
style: object,
/**
* Pixel value from the top of the document. When scrolled passed, the
* sticky header is no longer sticky, and renders normally.
*/
lowerBound: number,
/**
* Width of section when it sticks to the top edge of the screen. When
* omitted, it defaults to the last width of the section.
*/
viewportWidth: number,
},
getInitialState() {
return {
isAboveFold: false,
containerRect: {},
};
},
handleScroll() {
const {
lowerBound,
} = this.props;
const {
isAboveFold,
containerRect,
} = this.state;
const nextContainerRect = this.getContainerRect();
Eif (window.pageYOffset >= nextContainerRect.top) {
if (!isAboveFold) {
this.setState({
isAboveFold: true,
});
}
} else {
if (isAboveFold) {
this.setState({
isAboveFold: false,
});
}
}
if (_.isNumber(lowerBound) && window.pageYOffset >= lowerBound) {
this.setState({
isAboveFold: false,
});
}
Eif (
containerRect.bottom !== nextContainerRect.bottom
|| containerRect.height !== nextContainerRect.height
|| containerRect.left !== nextContainerRect.left
|| containerRect.right !== nextContainerRect.right
|| containerRect.top !== nextContainerRect.top
|| containerRect.width !== nextContainerRect.width
|| containerRect.scrollWidth !== nextContainerRect.scrollWidth
|| containerRect.frameLeft !== nextContainerRect.frameLeft
) {
this.setState({
containerRect: nextContainerRect,
});
}
},
getContainerRect() {
const containerRect = getAbsoluteBoundingClientRect(this.refs.scrollContainer);
const stickyRect = this.refs.stickySection.getBoundingClientRect();
const frameRect = this.refs.stickyFrame.getBoundingClientRect();
return {
bottom: containerRect.top + stickyRect.height,
height: stickyRect.height,
left: containerRect.left,
right: containerRect.left + stickyRect.width,
top: containerRect.top,
scrollWidth: this.refs.stickySection.scrollWidth,
width: containerRect.width,
frameLeft: frameRect.left,
};
},
componentDidMount() {
setTimeout(() => {
this.setState({
containerRect: this.getContainerRect(),
});
this.handleScroll();
}, 1);
window.addEventListener('scroll', this.handleScroll, true);
},
componentWillUnmount() {
window.removeEventListener('scroll', this.handleScroll, true);
},
render() {
const {
children,
className,
style,
viewportWidth,
...passThroughs,
} = this.props;
const {
isAboveFold,
containerRect,
} = this.state;
return (
<div
{...omitProps(passThroughs, StickySection)}
className={cx('&', className)}
style={{
...(isAboveFold ? {
height: containerRect.height,
} : {}),
...style,
}}
ref='scrollContainer'
>
<div
className={cx('&-sticky-frame')}
ref='stickyFrame'
style={{
...(isAboveFold ? {
position: 'fixed',
top: 0,
width: (_.isNumber(viewportWidth) ? viewportWidth : containerRect.width),
height: containerRect.height,
overflow: 'hidden',
} : {}),
...style,
}}
>
<div
className={cx('&-sticky-section')}
ref='stickySection'
style={{
...(isAboveFold ? {
position: 'absolute',
top: 0,
left: (containerRect.left - containerRect.frameLeft) || 0,
width: containerRect.scrollWidth,
height: containerRect.height,
} : {
position: 'relative',
}),
...style,
}}
>
{children}
</div>
</div>
</div>
);
},
});
export default StickySection;
|