planning

node_modules/teeny-tap/index.js

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+module.exports = function createTapListener(el, callback, useCapture) {
+  var startX = 0;
+  var startY = 0;
+  var touchStarted = false;
+  var touchMoved = false;
+  // Assume that if a touchstart event initiates, the user is
+  // using touch and click events should be ignored.
+  // If this isn't done, touch-clicks will fire the callback
+  // twice: once on touchend, once on the subsequent "click".
+  var usingTouch = false;
+
+  el.addEventListener('click', handleClick, useCapture);
+  el.addEventListener('touchstart', handleTouchstart, useCapture);
+
+  function handleClick(e) {
+    if (usingTouch) return;
+    callback(e);
+  }
+
+  function handleTouchstart(e) {
+    usingTouch = true;
+
+    if (touchStarted) return;
+    touchStarted = true;
+
+    el.addEventListener('touchmove', handleTouchmove, useCapture);
+    el.addEventListener('touchend', handleTouchend, useCapture);
+    el.addEventListener('touchcancel', handleTouchcancel, useCapture);
+
+    touchMoved = false;
+    startX = e.touches[0].clientX;
+    startY = e.touches[0].clientY;
+  }
+
+  function handleTouchmove(e) {
+    if (touchMoved) return;
+
+    if (
+      Math.abs(e.touches[0].clientX - startX) <= 10
+      && Math.abs(e.touches[0].clientY - startY) <= 10
+    ) return;
+
+    touchMoved = true;
+  }
+
+  function handleTouchend(e) {
+    touchStarted = false;
+    removeSecondaryTouchListeners();
+    if (!touchMoved) {
+      callback(e);
+    }
+  }
+
+  function handleTouchcancel() {
+    touchStarted = false;
+    touchMoved = false;
+    startX = 0;
+    startY = 0;
+  }
+
+  function removeSecondaryTouchListeners() {
+    el.removeEventListener('touchmove', handleTouchmove, useCapture);
+    el.removeEventListener('touchend', handleTouchend, useCapture);
+    el.removeEventListener('touchcancel', handleTouchcancel, useCapture);
+  }
+
+  function removeTapListener() {
+    el.removeEventListener('click', handleClick, useCapture);
+    el.removeEventListener('touchstart', handleTouchstart, useCapture);
+    removeSecondaryTouchListeners();
+  }
+
+  return {
+    remove: removeTapListener,
+  };
+};