104 lines
2.3 KiB
JavaScript
104 lines
2.3 KiB
JavaScript
"use strict";
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/**
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* Simple slideout menu implementation.
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*/
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module.exports = function slideoutMenu(viewport, menu) {
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let touchStartPos = null;
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let touchCurPos = null;
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let touchStartTime = 0;
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let menuWidth = 0;
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let menuIsOpen = false;
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let menuIsMoving = false;
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function toggleMenu(state) {
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menuIsOpen = state;
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viewport.classList.toggle("menu-open", state);
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}
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function disableSlideout() {
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viewport.removeEventListener("ontouchstart", onTouchStart);
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}
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function onTouchStart(e) {
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if (e.touches.length !== 1) {
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onTouchEnd();
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return;
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}
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const touch = e.touches.item(0);
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viewport.classList.toggle("menu-dragging", true);
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menuWidth = parseFloat(window.getComputedStyle(menu).width);
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if ((!menuIsOpen && touch.screenX < 50) || (menuIsOpen && touch.screenX > menuWidth)) {
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touchStartPos = touch;
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touchCurPos = touch;
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touchStartTime = Date.now();
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viewport.addEventListener("touchmove", onTouchMove);
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viewport.addEventListener("touchend", onTouchEnd, {passive: true});
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}
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}
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function onTouchMove(e) {
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const touch = touchCurPos = e.touches.item(0);
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let setX = touch.screenX - touchStartPos.screenX;
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if (Math.abs(setX > 30)) {
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menuIsMoving = true;
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}
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if (!menuIsMoving && Math.abs(touch.screenY - touchStartPos.screenY) > 30) {
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onTouchEnd();
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return;
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}
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if (menuIsOpen) {
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setX += menuWidth;
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}
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if (setX > menuWidth) {
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setX = menuWidth;
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} else if (setX < 0) {
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setX = 0;
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}
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viewport.style.transform = "translate3d(" + setX + "px, 0, 0)";
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if (menuIsMoving) {
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e.preventDefault();
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e.stopPropagation();
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}
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}
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function onTouchEnd() {
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const diff = touchCurPos.screenX - touchStartPos.screenX;
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const absDiff = Math.abs(diff);
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if (absDiff > menuWidth / 2 || Date.now() - touchStartTime < 180 && absDiff > 50) {
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toggleMenu(diff > 0);
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}
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viewport.removeEventListener("touchmove", onTouchMove);
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viewport.removeEventListener("touchend", onTouchEnd);
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viewport.classList.toggle("menu-dragging", false);
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viewport.style.transform = null;
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touchStartPos = null;
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touchCurPos = null;
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touchStartTime = 0;
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menuIsMoving = false;
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}
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viewport.addEventListener("touchstart", onTouchStart, {passive: true});
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return {
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disable: disableSlideout,
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toggle: toggleMenu,
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isOpen: function() {
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return menuIsOpen;
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},
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};
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};
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