[improvement] mixins typescript (#3690)

src/mixins/click-outside.ts

@@ -0,0 +1,31 @@
+/**
+ * Listen to click outside event
+ */
+import Vue from 'vue';
+import { on, off } from '../utils/dom/event';
+
+export type ClickOutsideMixinConfig = {
+  event: string;
+  method: string;
+};
+
+export const ClickOutsideMixin = (config: ClickOutsideMixinConfig) =>
+  Vue.extend({
+    data() {
+      const clickOutsideHandler = (event: Event) => {
+        if (!this.$el.contains(event.target as Node)) {
+          (this as any)[config.method]();
+        }
+      };
+
+      return { clickOutsideHandler };
+    },
+
+    mounted() {
+      on(document, config.event, this.clickOutsideHandler);
+    },
+
+    beforeDestroy() {
+      off(document, config.event, this.clickOutsideHandler);
+    }
+  });