perf(@vant/use): reduce usePageVisibility event binding (#9835)

* perf(@vant/use): reduce usePageVisibility event binding * chore: update
2021-11-11 17:25:48 +08:00
parent a9ce9096e4
commit a0b368f1b4
4 changed files with 21 additions and 23 deletions
@@ -1,18 +1,21 @@
-import { ref } from 'vue';
+import { ref, Ref } from 'vue';
 import { inBrowser } from '../utils';
-import { useEventListener } from '../useEventListener';
+
+let visibility: Ref<VisibilityState>;

 export function usePageVisibility() {
-  const visibility = ref<VisibilityState>('visible');
+  if (!visibility) {
+    visibility = ref<VisibilityState>('visible');

-  const setVisibility = () => {
    if (inBrowser) {
-      visibility.value = document.hidden ? 'hidden' : 'visible';
-    }
-  };
+      const update = () => {
+        visibility.value = document.hidden ? 'hidden' : 'visible';
+      };

-  setVisibility();
-  useEventListener('visibilitychange', setVisibility);
+      update();
+      window.addEventListener('visibilitychange', update);
+    }
+  }

  return visibility;
 }