inferno-window
Version:
Inferno components for efficiently rendering large, scrollable lists and tabular data. NOTE: this is a port from the origin project written in react by @bvaughn
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JavaScript
// @flow
import memoizeOne from 'memoize-one';
import { createElement } from 'inferno-create-element';
import { PureComponent } from './PureComponent';
import { cancelTimeout, requestTimeout } from './timer';
import type { TimeoutID } from './timer';
export type ScrollToAlign = 'auto' | 'center' | 'start' | 'end';
type itemSize = number | ((index: number) => number);
// TODO Deprecate directions "horizontal" and "vertical"
type Direction = 'ltr' | 'rtl' | 'horizontal' | 'vertical';
type Layout = 'horizontal' | 'vertical';
type RenderComponentProps<T> = {|
data: T,
index: number,
isScrolling?: boolean,
style: Object,
|};
type RenderComponent<T> = React$ComponentType<$Shape<RenderComponentProps<T>>>;
type ScrollDirection = 'forward' | 'backward';
type onItemsRenderedCallback = ({
overscanStartIndex: number,
overscanStopIndex: number,
visibleStartIndex: number,
visibleStopIndex: number,
}) => void;
type onScrollCallback = ({
scrollDirection: ScrollDirection,
scrollOffset: number,
scrollUpdateWasRequested: boolean,
}) => void;
type ScrollEvent = SyntheticEvent<HTMLDivElement>;
type ItemStyleCache = { [index: number]: Object };
export type Props<T> = {|
children: RenderComponent<T>,
className?: string,
direction: Direction,
height: number | string,
initialScrollOffset?: number,
innerRef?: any,
innerElementType?: React$ElementType,
innerTagName?: string, // deprecated
itemCount: number,
itemData: T,
itemKey?: (index: number, data: T) => any,
itemSize: itemSize,
layout: Layout,
onItemsRendered?: onItemsRenderedCallback,
onScroll?: onScrollCallback,
outerRef?: any,
outerElementType?: React$ElementType,
outerTagName?: string, // deprecated
overscanCount: number,
style?: Object,
useIsScrolling: boolean,
width: number | string,
|};
type State = {|
instance: any,
isScrolling: boolean,
scrollDirection: ScrollDirection,
scrollOffset: number,
scrollUpdateWasRequested: boolean,
|};
type GetItemOffset = (
props: Props<any>,
index: number,
instanceProps: any
) => number;
type GetItemSize = (
props: Props<any>,
index: number,
instanceProps: any
) => number;
type GetEstimatedTotalSize = (props: Props<any>, instanceProps: any) => number;
type GetOffsetForIndexAndAlignment = (
props: Props<any>,
index: number,
align: ScrollToAlign,
scrollOffset: number,
instanceProps: any
) => number;
type GetStartIndexForOffset = (
props: Props<any>,
offset: number,
instanceProps: any
) => number;
type GetStopIndexForStartIndex = (
props: Props<any>,
startIndex: number,
scrollOffset: number,
instanceProps: any
) => number;
type InitInstanceProps = (props: Props<any>, instance: any) => any;
type ValidateProps = (props: Props<any>) => void;
const IS_SCROLLING_DEBOUNCE_INTERVAL = 150;
const defaultItemKey = (index: number, data: any) => index;
// In DEV mode, this Set helps us only log a warning once per component instace.
// This avoids spamming the console every time a render happens.
let devWarningsDirection = null;
let devWarningsTagName = null;
if (process.env.NODE_ENV !== 'production') {
if (typeof window !== 'undefined' && typeof window.WeakSet !== 'undefined') {
devWarningsDirection = new WeakSet();
devWarningsTagName = new WeakSet();
}
}
export default function createListComponent({
getItemOffset,
getEstimatedTotalSize,
getItemSize,
getOffsetForIndexAndAlignment,
getStartIndexForOffset,
getStopIndexForStartIndex,
initInstanceProps,
shouldResetStyleCacheOnItemSizeChange,
validateProps,
}: {|
getItemOffset: GetItemOffset,
getEstimatedTotalSize: GetEstimatedTotalSize,
getItemSize: GetItemSize,
getOffsetForIndexAndAlignment: GetOffsetForIndexAndAlignment,
getStartIndexForOffset: GetStartIndexForOffset,
getStopIndexForStartIndex: GetStopIndexForStartIndex,
initInstanceProps: InitInstanceProps,
shouldResetStyleCacheOnItemSizeChange: boolean,
validateProps: ValidateProps,
|}) {
return class List<T> extends PureComponent<Props<T>, State> {
_instanceProps: any = initInstanceProps(this.props, this);
_outerRef: ?HTMLDivElement;
_resetIsScrollingTimeoutId: TimeoutID | null = null;
static defaultProps = {
direction: 'ltr',
itemData: undefined,
layout: 'vertical',
overscanCount: 2,
useIsScrolling: false,
};
state: State = {
instance: this,
isScrolling: false,
scrollDirection: 'forward',
scrollOffset:
typeof this.props.initialScrollOffset === 'number'
? this.props.initialScrollOffset
: 0,
scrollUpdateWasRequested: false,
};
// Always use explicit constructor for React components.
// It produces less code after transpilation. (#26)
// eslint-disable-next-line no-useless-constructor
constructor(props: Props<T>) {
super(props);
}
static getDerivedStateFromProps(
nextProps: Props<T>,
prevState: State
): $Shape<State> | null {
validateSharedProps(nextProps, prevState);
validateProps(nextProps);
return null;
}
scrollTo(scrollOffset: number): void {
this.setState(
prevState => ({
scrollDirection:
prevState.scrollOffset < scrollOffset ? 'forward' : 'backward',
scrollOffset: scrollOffset,
scrollUpdateWasRequested: true,
}),
this._resetIsScrollingDebounced
);
}
scrollToItem(index: number, align: ScrollToAlign = 'auto'): void {
const { scrollOffset } = this.state;
this.scrollTo(
getOffsetForIndexAndAlignment(
this.props,
index,
align,
scrollOffset,
this._instanceProps
)
);
}
componentDidMount() {
const { direction, initialScrollOffset, layout } = this.props;
if (typeof initialScrollOffset === 'number' && this._outerRef !== null) {
// TODO Deprecate direction "horizontal"
if (direction === 'horizontal' || layout === 'horizontal') {
((this
._outerRef: any): HTMLDivElement).scrollLeft = initialScrollOffset;
} else {
((this
._outerRef: any): HTMLDivElement).scrollTop = initialScrollOffset;
}
}
this._callPropsCallbacks();
}
componentDidUpdate() {
const { direction, layout } = this.props;
const { scrollOffset, scrollUpdateWasRequested } = this.state;
if (scrollUpdateWasRequested && this._outerRef !== null) {
// TODO Deprecate direction "horizontal"
if (direction === 'horizontal' || layout === 'horizontal') {
((this._outerRef: any): HTMLDivElement).scrollLeft = scrollOffset;
} else {
((this._outerRef: any): HTMLDivElement).scrollTop = scrollOffset;
}
}
this._callPropsCallbacks();
}
componentWillUnmount() {
if (this._resetIsScrollingTimeoutId !== null) {
cancelTimeout(this._resetIsScrollingTimeoutId, this._outerRef);
}
}
render() {
const {
children,
className,
direction,
height,
innerRef,
innerElementType,
innerTagName,
itemCount,
itemData,
itemKey = defaultItemKey,
layout,
outerElementType,
outerTagName,
style,
useIsScrolling,
width,
} = this.props;
const { isScrolling } = this.state;
// TODO Deprecate direction "horizontal"
const isHorizontal =
direction === 'horizontal' || layout === 'horizontal';
const onScroll = isHorizontal
? this._onScrollHorizontal
: this._onScrollVertical;
const [startIndex, stopIndex] = this._getRangeToRender();
const items = [];
if (itemCount > 0) {
for (let index = startIndex; index <= stopIndex; index++) {
items.push(
createElement(children, {
data: itemData,
key: itemKey(index, itemData),
index,
isScrolling: useIsScrolling ? isScrolling : undefined,
style: this._getItemStyle(index),
})
);
}
}
// Read this value AFTER items have been created,
// So their actual sizes (if variable) are taken into consideration.
const estimatedTotalSize = getEstimatedTotalSize(
this.props,
this._instanceProps
);
return createElement(
outerElementType || outerTagName || 'div',
{
className,
onScroll,
ref: this._outerRefSetter,
style: {
position: 'relative',
height: `${height}px`,
width: `${width}px`,
overflow: 'auto',
WebkitOverflowScrolling: 'touch',
'will-change': 'transform',
direction,
...style,
},
},
createElement(innerElementType || innerTagName || 'div', {
children: items,
ref: innerRef,
style: {
height: isHorizontal ? '100%' : `${estimatedTotalSize}px`,
pointerEvents: isScrolling ? 'none' : '',
width: isHorizontal ? `${estimatedTotalSize}px` : '100%',
},
})
);
}
_callOnItemsRendered: (
overscanStartIndex: number,
overscanStopIndex: number,
visibleStartIndex: number,
visibleStopIndex: number
) => void;
_callOnItemsRendered = memoizeOne(
(
overscanStartIndex: number,
overscanStopIndex: number,
visibleStartIndex: number,
visibleStopIndex: number
) =>
((this.props.onItemsRendered: any): onItemsRenderedCallback)({
overscanStartIndex,
overscanStopIndex,
visibleStartIndex,
visibleStopIndex,
})
);
_callOnScroll: (
scrollDirection: ScrollDirection,
scrollOffset: number,
scrollUpdateWasRequested: boolean
) => void;
_callOnScroll = memoizeOne(
(
scrollDirection: ScrollDirection,
scrollOffset: number,
scrollUpdateWasRequested: boolean
) =>
((this.props.onScroll: any): onScrollCallback)({
scrollDirection,
scrollOffset,
scrollUpdateWasRequested,
})
);
_callPropsCallbacks() {
if (typeof this.props.onItemsRendered === 'function') {
const { itemCount } = this.props;
if (itemCount > 0) {
const [
overscanStartIndex,
overscanStopIndex,
visibleStartIndex,
visibleStopIndex,
] = this._getRangeToRender();
this._callOnItemsRendered(
overscanStartIndex,
overscanStopIndex,
visibleStartIndex,
visibleStopIndex
);
}
}
if (typeof this.props.onScroll === 'function') {
const {
scrollDirection,
scrollOffset,
scrollUpdateWasRequested,
} = this.state;
this._callOnScroll(
scrollDirection,
scrollOffset,
scrollUpdateWasRequested
);
}
}
// Lazily create and cache item styles while scrolling,
// So that pure component sCU will prevent re-renders.
// We maintain this cache, and pass a style prop rather than index,
// So that List can clear cached styles and force item re-render if necessary.
_getItemStyle: (index: number) => Object;
_getItemStyle = (index: number): Object => {
const { direction, itemSize, layout } = this.props;
const itemStyleCache = this._getItemStyleCache(
shouldResetStyleCacheOnItemSizeChange && itemSize,
shouldResetStyleCacheOnItemSizeChange && layout,
shouldResetStyleCacheOnItemSizeChange && direction
);
let style;
if (itemStyleCache.hasOwnProperty(index)) {
style = itemStyleCache[index];
} else {
const offset = getItemOffset(this.props, index, this._instanceProps);
const size = getItemSize(this.props, index, this._instanceProps);
// TODO Deprecate direction "horizontal"
const isHorizontal =
direction === 'horizontal' || layout === 'horizontal';
itemStyleCache[index] = style = {
position: 'absolute',
[direction === 'rtl' ? 'right' : 'left']: isHorizontal ? offset : 0,
top: !isHorizontal ? `${offset}px` : 0,
height: !isHorizontal ? `${size}px` : '100%',
width: isHorizontal ? `${size}px` : '100%',
};
}
return style;
};
_getItemStyleCache: (_: any, __: any, ___: any) => ItemStyleCache;
_getItemStyleCache = memoizeOne((_: any, __: any, ___: any) => ({}));
_getRangeToRender(): [number, number, number, number] {
const { itemCount, overscanCount } = this.props;
const { isScrolling, scrollDirection, scrollOffset } = this.state;
if (itemCount === 0) {
return [0, 0, 0, 0];
}
const startIndex = getStartIndexForOffset(
this.props,
scrollOffset,
this._instanceProps
);
const stopIndex = getStopIndexForStartIndex(
this.props,
startIndex,
scrollOffset,
this._instanceProps
);
// Overscan by one item in each direction so that tab/focus works.
// If there isn't at least one extra item, tab loops back around.
const overscanBackward =
!isScrolling || scrollDirection === 'backward'
? Math.max(1, overscanCount)
: 1;
const overscanForward =
!isScrolling || scrollDirection === 'forward'
? Math.max(1, overscanCount)
: 1;
return [
Math.max(0, startIndex - overscanBackward),
Math.max(0, Math.min(itemCount - 1, stopIndex + overscanForward)),
startIndex,
stopIndex,
];
}
_onScrollHorizontal = (event: ScrollEvent): void => {
const { clientWidth, scrollLeft, scrollWidth } = event.currentTarget;
this.setState(prevState => {
if (prevState.scrollOffset === scrollLeft) {
// Scroll position may have been updated by cDM/cDU,
// In which case we don't need to trigger another render,
// And we don't want to update state.isScrolling.
return null;
}
const { direction } = this.props;
// HACK According to the spec, scrollLeft should be negative for RTL aligned elements.
// Chrome does not seem to adhere; its scrolLeft values are positive (measured relative to the left).
// See https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollLeft
let scrollOffset = scrollLeft;
if (direction === 'rtl') {
if (scrollLeft <= 0) {
scrollOffset = -scrollOffset;
} else {
scrollOffset = scrollWidth - clientWidth - scrollLeft;
}
}
return {
isScrolling: true,
scrollDirection:
prevState.scrollOffset < scrollLeft ? 'forward' : 'backward',
scrollOffset,
scrollUpdateWasRequested: false,
};
}, this._resetIsScrollingDebounced);
};
_onScrollVertical = (event: ScrollEvent): void => {
const { scrollTop } = event.currentTarget;
this.setState(prevState => {
if (prevState.scrollOffset === scrollTop) {
// Scroll position may have been updated by cDM/cDU,
// In which case we don't need to trigger another render,
// And we don't want to update state.isScrolling.
return null;
}
return {
isScrolling: true,
scrollDirection:
prevState.scrollOffset < scrollTop ? 'forward' : 'backward',
scrollOffset: scrollTop,
scrollUpdateWasRequested: false,
};
}, this._resetIsScrollingDebounced);
};
_outerRefSetter = (ref: any): void => {
const { outerRef } = this.props;
this._outerRef = ((ref: any): HTMLDivElement);
if (typeof outerRef === 'function') {
outerRef(ref);
} else if (
outerRef != null &&
typeof outerRef === 'object' &&
outerRef.hasOwnProperty('current')
) {
outerRef.current = ref;
}
};
_resetIsScrollingDebounced = () => {
if (this._resetIsScrollingTimeoutId !== null) {
cancelTimeout(this._resetIsScrollingTimeoutId, this._outerRef);
}
this._resetIsScrollingTimeoutId = requestTimeout(
this._resetIsScrolling,
IS_SCROLLING_DEBOUNCE_INTERVAL,
this._outerRef
);
};
_resetIsScrolling = () => {
this._resetIsScrollingTimeoutId = null;
this.setState({ isScrolling: false }, () => {
// Clear style cache after state update has been committed.
// This way we don't break pure sCU for items that don't use isScrolling param.
this._getItemStyleCache(-1, null);
});
};
};
}
// NOTE: I considered further wrapping individual items with a pure ListItem component.
// This would avoid ever calling the render function for the same index more than once,
// But it would also add the overhead of a lot of components/fibers.
// I assume people already do this (render function returning a class component),
// So my doing it would just unnecessarily double the wrappers.
const validateSharedProps = (
{
children,
direction,
height,
layout,
innerTagName,
outerTagName,
width,
}: Props<any>,
{ instance }: State
): void => {
if (process.env.NODE_ENV !== 'production') {
if (innerTagName != null || outerTagName != null) {
if (devWarningsTagName && !devWarningsTagName.has(instance)) {
devWarningsTagName.add(instance);
console.warn(
'The innerTagName and outerTagName props have been deprecated. ' +
'Please use the innerElementType and outerElementType props instead.'
);
}
}
// TODO Deprecate direction "horizontal"
const isHorizontal = direction === 'horizontal' || layout === 'horizontal';
switch (direction) {
case 'horizontal':
case 'vertical':
if (devWarningsDirection && !devWarningsDirection.has(instance)) {
devWarningsDirection.add(instance);
console.warn(
'The direction prop should be either "ltr" (default) or "rtl". ' +
'Please use the layout prop to specify "vertical" (default) or "horizontal" orientation.'
);
}
break;
case 'ltr':
case 'rtl':
// Valid values
break;
default:
throw Error(
'An invalid "direction" prop has been specified. ' +
'Value should be either "ltr" or "rtl". ' +
`"${direction}" was specified.`
);
}
switch (layout) {
case 'horizontal':
case 'vertical':
// Valid values
break;
default:
throw Error(
'An invalid "layout" prop has been specified. ' +
'Value should be either "horizontal" or "vertical". ' +
`"${layout}" was specified.`
);
}
if (children == null) {
throw Error(
'An invalid "children" prop has been specified. ' +
'Value should be a React component. ' +
`"${children === null ? 'null' : typeof children}" was specified.`
);
}
if (isHorizontal && typeof width !== 'number') {
throw Error(
'An invalid "width" prop has been specified. ' +
'Horizontal lists must specify a number for width. ' +
`"${width === null ? 'null' : typeof width}" was specified.`
);
} else if (!isHorizontal && typeof height !== 'number') {
throw Error(
'An invalid "height" prop has been specified. ' +
'Vertical lists must specify a number for height. ' +
`"${height === null ? 'null' : typeof height}" was specified.`
);
}
}
};