update the master branch to the latest

types/back-top.d.ts

@@ -0,0 +1,32 @@
+// Type definitions for iview 3.3.1
+// Project: https://github.com/iview/iview
+// Definitions by: yangdan
+// Definitions: https://github.com/yangdan8/iview.git
+import Vue from 'vue';
+
+export declare class BackTop extends Vue {
+  /**
+   * 页面滚动高度达到该值时才显示BackTop组件
+   * @default 400
+   */
+  height?: number;
+  /**
+   * 组件距离底部的距离
+   * @default 30
+   */
+  bottom?: number;
+  /**
+   * 组件距离右部的距离
+   * @default 30
+   */
+  right?: number;
+  /**
+   * 滚动动画持续时间，单位 毫秒
+   * @default 1000
+   */
+  duration?: number;
+  /**
+   * 点击按钮时触发
+   */
+  $emit(eventName: 'on-click'): this;
+}