perf: improve the performance of getNow (#5944)

zhangenming · web-flow · commit 3bdc41dff305 · 2022-05-22T20:36:57.000-04:00
diff --git a/packages/runtime-dom/src/modules/events.ts b/packages/runtime-dom/src/modules/events.ts
@@ -25,7 +25,7 @@ const [_getNow, skipTimestampCheck] = /*#__PURE__*/ (() => {
       // if the low-res timestamp which is bigger than the event timestamp
       // (which is evaluated AFTER) it means the event is using a hi-res timestamp,
       // and we need to use the hi-res version for event listeners as well.
-      _getNow = () => performance.now()
+      _getNow = performance.now.bind(performance)
     }
     // #3485: Firefox <= 53 has incorrect Event.timeStamp implementation
     // and does not fire microtasks in between event propagation, so safe to exclude.

Original file line number	Diff line number	Diff line change
`@@ -25,7 +25,7 @@ const [_getNow, skipTimestampCheck] = /#__PURE__/ (() => {`
`25`	`25`	`// if the low-res timestamp which is bigger than the event timestamp`
`26`	`26`	`// (which is evaluated AFTER) it means the event is using a hi-res timestamp,`
`27`	`27`	`// and we need to use the hi-res version for event listeners as well.`
`28`		`- _getNow = () => performance.now()`
	`28`	`+ _getNow = performance.now.bind(performance)`
`29`	`29`	`}`
`30`	`30`	`// #3485: Firefox <= 53 has incorrect Event.timeStamp implementation`
`31`	`31`	`// and does not fire microtasks in between event propagation, so safe to exclude.`