From ec5067ce7dce5da487f1b5cc10bce1dadd2ed84c Mon Sep 17 00:00:00 2001
From: neverland <chenjiahan@youzan.com>
Date: Wed, 29 Sep 2021 17:36:50 +0800
Subject: [PATCH] perf: remove passive event polyfill (#9590)

---
 packages/vant-lazyload/src/util.js            | 31 +++----------------
 .../vant-use/src/useEventListener/index.ts    | 22 +------------
 .../vant/src/composables/use-lock-scroll.ts   | 12 ++-----
 3 files changed, 7 insertions(+), 58 deletions(-)

diff --git a/packages/vant-lazyload/src/util.js b/packages/vant-lazyload/src/util.js
index 704c75591..46fb4ca49 100644
--- a/packages/vant-lazyload/src/util.js
+++ b/packages/vant-lazyload/src/util.js
@@ -135,35 +135,12 @@ function throttle(action, delay) {
   };
 }
 
-function testSupportsPassive() {
-  if (!inBrowser) return;
-  let support = false;
-  try {
-    const opts = Object.defineProperty({}, 'passive', {
-      // eslint-disable-next-line getter-return
-      get() {
-        support = true;
-      },
-    });
-    window.addEventListener('test', null, opts);
-  } catch (e) {
-    //
-  }
-  return support;
-}
-
-const supportsPassive = testSupportsPassive();
-
 const _ = {
   on(el, type, func, capture = false) {
-    if (supportsPassive) {
-      el.addEventListener(type, func, {
-        capture,
-        passive: true,
-      });
-    } else {
-      el.addEventListener(type, func, capture);
-    }
+    el.addEventListener(type, func, {
+      capture,
+      passive: true,
+    });
   },
   off(el, type, func, capture = false) {
     el.removeEventListener(type, func, capture);
diff --git a/packages/vant-use/src/useEventListener/index.ts b/packages/vant-use/src/useEventListener/index.ts
index e4ec9f5c5..01f6d1c8e 100644
--- a/packages/vant-use/src/useEventListener/index.ts
+++ b/packages/vant-use/src/useEventListener/index.ts
@@ -2,22 +2,6 @@ import { Ref, watch, isRef, unref, onUnmounted, onDeactivated } from 'vue';
 import { onMountedOrActivated } from '../onMountedOrActivated';
 import { inBrowser } from '../utils';
 
-// eslint-disable-next-line
-export let supportsPassive = false;
-
-if (inBrowser) {
-  try {
-    const opts = {};
-    Object.defineProperty(opts, 'passive', {
-      get() {
-        supportsPassive = true;
-      },
-    });
-    window.addEventListener('test-passive', null as any, opts);
-    // eslint-disable-next-line no-empty
-  } catch (e) {}
-}
-
 type TargetRef = EventTarget | Ref<EventTarget | undefined>;
 
 export type UseEventListenerOptions = {
@@ -43,11 +27,7 @@ export function useEventListener(
     const element = unref(target);
 
     if (element && !attached) {
-      element.addEventListener(
-        type,
-        listener,
-        supportsPassive ? { capture, passive } : capture
-      );
+      element.addEventListener(type, listener, { capture, passive });
       attached = true;
     }
   };
diff --git a/packages/vant/src/composables/use-lock-scroll.ts b/packages/vant/src/composables/use-lock-scroll.ts
index 642b01b44..dacc64229 100644
--- a/packages/vant/src/composables/use-lock-scroll.ts
+++ b/packages/vant/src/composables/use-lock-scroll.ts
@@ -1,9 +1,5 @@
 import { Ref, watch, onBeforeUnmount, onDeactivated } from 'vue';
-import {
-  getScrollParent,
-  supportsPassive,
-  onMountedOrActivated,
-} from '@vant/use';
+import { getScrollParent, onMountedOrActivated } from '@vant/use';
 import { useTouch } from './use-touch';
 import { preventDefault } from '../utils';
 
@@ -45,11 +41,7 @@ export function useLockScroll(
 
   const lock = () => {
     document.addEventListener('touchstart', touch.start);
-    document.addEventListener(
-      'touchmove',
-      onTouchMove,
-      supportsPassive ? { passive: false } : false
-    );
+    document.addEventListener('touchmove', onTouchMove, { passive: false });
 
     if (!totalLockCount) {
       document.body.classList.add(BODY_LOCK_CLASS);