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"use strict";
const direction = {
NONE: null,
LEFT: "left",
RIGHT: "right",
DOWN: "down",
UP: "up",
};
function handleTouchStart(handler, evt) {
const touchEvent = evt.touches[0];
handler._xStart = touchEvent.clientX;
handler._yStart = touchEvent.clientY;
}
function handleTouchMove(handler, evt) {
if (!handler._xStart || !handler._yStart) {
return;
}
const xDirection = handler._xStart - evt.touches[0].clientX;
const yDirection = handler._yStart - evt.touches[0].clientY;
if (Math.abs(xDirection) > Math.abs(yDirection)) {
if (xDirection > 0) {
handler._direction = direction.LEFT;
} else {
handler._direction = direction.RIGHT;
}
} else if (yDirection > 0) {
handler._direction = direction.DOWN;
} else {
handler._direction = direction.UP;
}
}
function handleTouchEnd(handler) {
switch (handler._direction) {
case direction.NONE:
return;
case direction.LEFT:
handler._swipeLeftTask();
break;
case direction.RIGHT:
handler._swipeRightTask();
break;
case direction.DOWN:
handler._swipeDownTask();
break;
case direction.UP:
handler._swipeUpTask();
// no default
}
handler._xStart = null;
handler._yStart = null;
}
class Touch {
constructor(
target,
swipeLeft = () => {},
swipeRight = () => {},
swipeUp = () => {},
swipeDown = () => {}
) {
this._target = target;
this._swipeLeftTask = swipeLeft;
this._swipeRightTask = swipeRight;
this._swipeUpTask = swipeUp;
this._swipeDownTask = swipeDown;
this._xStart = null;
this._yStart = null;
this._direction = direction.NONE;
this._target.addEventListener("touchstart", (evt) => {
handleTouchStart(this, evt);
});
this._target.addEventListener("touchmove", (evt) => {
handleTouchMove(this, evt);
});
this._target.addEventListener("touchend", () => {
handleTouchEnd(this);
});
}
}
module.exports = Touch;
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