[improvement] mixins typescript (#3690)

src/mixins/bind-event.ts

@@ -0,0 +1,31 @@
+/**
+ * Bind event when mounted or activated
+ */
+import { on, off } from '../utils/dom/event';
+
+type BindEventMixinThis = {
+  binded: boolean;
+};
+
+export function BindEventMixin(handler: Function) {
+  function bind(this: BindEventMixinThis) {
+    if (!this.binded) {
+      handler.call(this, on, true);
+      this.binded = true;
+    }
+  }
+
+  function unbind(this: BindEventMixinThis) {
+    if (this.binded) {
+      handler.call(this, off, false);
+      this.binded = false;
+    }
+  }
+
+  return {
+    mounted: bind,
+    activated: bind,
+    deactivated: unbind,
+    beforeDestroy: unbind
+  };
+}