tabs组件支持滑动 (#52)

packages/tab/src/swipe.js

@@ -0,0 +1,46 @@
+import Vue from 'vue';
+
+let isSwiping = false;
+
+const supportTouch = !Vue.prototype.$isServer && 'ontouchstart' in window;
+
+export default function(element, options) {
+  const moveFn = function(event) {
+    if (options.drag) {
+      options.drag(supportTouch ? event.changedTouches[0] || event.touches[0] : event);
+    }
+  };
+
+  const endFn = function(event) {
+    if (!supportTouch) {
+      document.removeEventListener('mousemove', moveFn);
+      document.removeEventListener('mouseup', endFn);
+    }
+
+    isSwiping = false;
+
+    if (options.end) {
+      options.end(supportTouch ? event.changedTouches[0] || event.touches[0] : event);
+    }
+  };
+
+  element.addEventListener(supportTouch ? 'touchstart' : 'mousedown', function(event) {
+    if (isSwiping) return;
+
+    if (!supportTouch) {
+      document.addEventListener('mousemove', moveFn);
+      document.addEventListener('mouseup', endFn);
+    }
+    isSwiping = true;
+
+    if (options.start) {
+      options.start(supportTouch ? event.changedTouches[0] || event.touches[0] : event);
+    }
+  });
+
+  if (supportTouch) {
+    element.addEventListener('touchmove', moveFn);
+    element.addEventListener('touchend', endFn);
+    element.addEventListener('touchcancel', endFn);
+  }
+};