[Improvement] add touch mixin (#869)

packages/mixins/touch.js

@@ -0,0 +1,25 @@
+export default {
+  methods: {
+    touchStart(event) {
+      this.direction = '';
+      this.deltaX = 0;
+      this.deltaY = 0;
+      this.offsetX = 0;
+      this.offsetY = 0;
+      this.startX = event.touches[0].clientX;
+      this.startY = event.touches[0].clientY;
+    },
+
+    touchMove(event) {
+      const touch = event.touches[0];
+      this.deltaX = touch.clientX - this.startX;
+      this.deltaY = touch.clientY - this.startY;
+      this.offsetX = Math.abs(this.deltaX);
+      this.offsetY = Math.abs(this.deltaY);
+
+      if (!this.direction) {
+        this.direction = this.offsetX > this.offsetY ? 'horizontal' : this.offsetX < this.offsetY ? 'vertical' : '';
+      }
+    }
+  }
+};