[improvement] move overlay component (#2192)

packages/overlay/index.vue

@@ -0,0 +1,34 @@
+<template>
+  <transition name="van-fade">
+    <div
+      v-show="visible"
+      class="van-overlay"
+      :class="className"
+      :style="style"
+      @touchmove.prevent.stop
+      @click="$emit('click', $event)"
+    />
+  </transition>
+</template>
+
+<script>
+export default {
+  name: 'overlay',
+
+  props: {
+    zIndex: Number,
+    visible: Boolean,
+    className: String,
+    customStyle: Object
+  },
+
+  computed: {
+    style() {
+      return {
+        zIndex: this.zIndex,
+        ...this.customStyle
+      };
+    }
+  }
+};
+</script>