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@cv2k10
Created February 14, 2021 04:02
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react-swipeable.js
// https://www.npmjs.com/package/react-swipeable
const { useRef, useMemo } = React;
const LEFT = "Left";
const RIGHT = "Right";
const UP = "Up";
const DOWN = "Down";
/* global document */
const defaultProps = {
delta: 10,
preventDefaultTouchmoveEvent: false,
rotationAngle: 0,
trackMouse: false,
trackTouch: true
};
const initialState = {
first: true,
initial: [0, 0],
start: 0,
swiping: false,
xy: [0, 0]
};
const mouseMove = "mousemove";
const mouseUp = "mouseup";
const touchEnd = "touchend";
const touchMove = "touchmove";
const touchStart = "touchstart";
function getDirection(absX, absY, deltaX, deltaY) {
if (absX > absY) {
if (deltaX > 0) {
return RIGHT;
}
return LEFT;
} else if (deltaY > 0) {
return DOWN;
}
return UP;
}
function rotateXYByAngle(pos, angle) {
if (angle === 0) return pos;
const angleInRadians = Math.PI / 180 * angle;
const x = pos[0] * Math.cos(angleInRadians) + pos[1] * Math.sin(angleInRadians);
const y = pos[1] * Math.cos(angleInRadians) - pos[0] * Math.sin(angleInRadians);
return [x, y];
}
function getHandlers(set, handlerProps) {
const onStart = event => {
// if more than a single touch don't track, for now...
if (event && "touches" in event && event.touches.length > 1) return;
set((state, props) => {
// setup mouse listeners on document to track swipe since swipe can leave container
if (props.trackMouse) {
document.addEventListener(mouseMove, onMove);
document.addEventListener(mouseUp, onUp);
}
const {
clientX,
clientY
} = "touches" in event ? event.touches[0] : event;
const xy = rotateXYByAngle([clientX, clientY], props.rotationAngle);
return { ...state,
...initialState,
initial: [...xy],
xy,
start: event.timeStamp || 0
};
});
};
const onMove = event => {
set((state, props) => {
// Discount a swipe if additional touches are present after
// a swipe has started.
if ("touches" in event && event.touches.length > 1) {
return state;
}
const {
clientX,
clientY
} = "touches" in event ? event.touches[0] : event;
const [x, y] = rotateXYByAngle([clientX, clientY], props.rotationAngle);
const deltaX = x - state.xy[0];
const deltaY = y - state.xy[1];
const absX = Math.abs(deltaX);
const absY = Math.abs(deltaY);
const time = (event.timeStamp || 0) - state.start;
const velocity = Math.sqrt(absX * absX + absY * absY) / (time || 1);
const vxvy = [deltaX / (time || 1), deltaY / (time || 1)]; // if swipe is under delta and we have not started to track a swipe: skip update
if (absX < props.delta && absY < props.delta && !state.swiping) return state;
const dir = getDirection(absX, absY, deltaX, deltaY);
const eventData = {
absX,
absY,
deltaX,
deltaY,
dir,
event,
first: state.first,
initial: state.initial,
velocity,
vxvy
};
props.onSwiping && props.onSwiping(eventData); // track if a swipe is cancelable(handler for swiping or swiped(dir) exists)
// so we can call preventDefault if needed
let cancelablePageSwipe = false;
if (props.onSwiping || props.onSwiped || `onSwiped${dir}` in props) {
cancelablePageSwipe = true;
}
if (cancelablePageSwipe && props.preventDefaultTouchmoveEvent && props.trackTouch && event.cancelable) event.preventDefault();
return { ...state,
// first is now always false
first: false,
eventData,
swiping: true
};
});
};
const onEnd = event => {
set((state, props) => {
let eventData;
if (state.swiping && state.eventData) {
eventData = { ...state.eventData,
event
};
props.onSwiped && props.onSwiped(eventData);
const onSwipedDir = `onSwiped${eventData.dir}`;
if (onSwipedDir in props) {
props[onSwipedDir](eventData);
}
} else {
props.onTap && props.onTap({
event
});
}
return { ...state,
...initialState,
eventData
};
});
};
const cleanUpMouse = () => {
// safe to just call removeEventListener
document.removeEventListener(mouseMove, onMove);
document.removeEventListener(mouseUp, onUp);
};
const onUp = e => {
cleanUpMouse();
onEnd(e);
};
/**
* Switch of "passive" property for now.
* When `preventDefaultTouchmoveEvent` is:
* - true => { passive: false }
* - false => { passive: true }
*
* Could take entire `addEventListener` options object as a param later?
*/
const attachTouch = (el, passive) => {
let cleanup = () => {};
if (el && el.addEventListener) {
// attach touch event listeners and handlers
const tls = [[touchStart, onStart], [touchMove, onMove], [touchEnd, onEnd]];
tls.forEach(([e, h]) => el.addEventListener(e, h, {
passive
})); // return properly scoped cleanup method for removing listeners, options not required
cleanup = () => tls.forEach(([e, h]) => el.removeEventListener(e, h));
}
return cleanup;
};
const onRef = el => {
// "inline" ref functions are called twice on render, once with null then again with DOM element
// ignore null here
if (el === null) return;
set((state, props) => {
// if the same DOM el as previous just return state
if (state.el === el) return state;
const addState = {}; // if new DOM el clean up old DOM and reset cleanUpTouch
if (state.el && state.el !== el && state.cleanUpTouch) {
state.cleanUpTouch();
addState.cleanUpTouch = undefined;
} // only attach if we want to track touch
if (props.trackTouch && el) {
addState.cleanUpTouch = attachTouch(el, !props.preventDefaultTouchmoveEvent);
} // store event attached DOM el for comparison, clean up, and re-attachment
return { ...state,
el,
...addState
};
});
}; // set ref callback to attach touch event listeners
const output = {
ref: onRef
}; // if track mouse attach mouse down listener
if (handlerProps.trackMouse) {
output.onMouseDown = onStart;
}
return [output, attachTouch];
}
function updateTransientState(state, props, attachTouch) {
const addState = {}; // clean up touch handlers if no longer tracking touches
if (!props.trackTouch && state.cleanUpTouch) {
state.cleanUpTouch();
addState.cleanUpTouch = undefined;
} else if (props.trackTouch && !state.cleanUpTouch) {
// attach/re-attach touch handlers
if (state.el) {
addState.cleanUpTouch = attachTouch(state.el, !props.preventDefaultTouchmoveEvent);
}
}
return { ...state,
...addState
};
}
function useSwipeable(options) {
const {
trackMouse
} = options;
const transientState = useRef({ ...initialState
});
const transientProps = useRef({ ...defaultProps
});
transientProps.current = { ...defaultProps,
...options
};
const [handlers, attachTouch] = useMemo(() => getHandlers(stateSetter => transientState.current = stateSetter(transientState.current, transientProps.current), {
trackMouse
}), [trackMouse]);
transientState.current = updateTransientState(transientState.current, transientProps.current, attachTouch);
return handlers;
}
// export { DOWN, LEFT, RIGHT, UP, useSwipeable };
//# sourceMappingURL=react-swipeable.modern.js.map
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