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