Guard against redefinition of Date.now (#1196)

* Guard against presence of likely older third party libraries which (re)define Date.now, e.g. https://github.com/datejs/Datejs/issues/92

* Apply formatting changes

* (remove nowTimestamp import where Date.now() is not used)

* Add a PURE marker so an empty `ìf` statement doesn't show up in the rrweb-replay output

* Update packages/rrweb/src/utils.ts

Fix typing issue with regex against `Date.now()`

Co-authored-by: Justin Halsall <Juice10@users.noreply.github.com>

* Create little-radios-thank.md

* Apply formatting changes

* Update .changeset/little-radios-thank.md

* Apply formatting changes

---------

Co-authored-by: eoghanmurray <eoghanmurray@users.noreply.github.com>
Co-authored-by: Justin Halsall <Juice10@users.noreply.github.com>

.changeset/date-now-guard.md

@@ -0,0 +1,5 @@
+---
+'rrweb': patch
+---
+
+Guard against presence of older 3rd party javascript libraries which redefine Date.now()

.changeset/little-radios-thank.md

@@ -0,0 +1,5 @@
+---
+'rrweb': patch
+---
+
+Guard against redefinition of Date.now by third party libraries which are also present on a page alongside rrweb

packages/rrweb/src/record/index.ts

@@ -14,6 +14,7 @@ import {
   hasShadowRoot,
   isSerializedIframe,
   isSerializedStylesheet,
+  nowTimestamp,
 } from '../utils';
 import type { recordOptions } from '../types';
 import {
@@ -42,7 +43,7 @@ import {
 function wrapEvent(e: event): eventWithTime {
   return {
     ...e,
-    timestamp: Date.now(),
+    timestamp: nowTimestamp(),
   };
 }
 

packages/rrweb/src/record/observer.ts

@@ -17,6 +17,7 @@ import {
   legacy_isTouchEvent,
   patch,
   StyleSheetMirror,
+  nowTimestamp,
 } from '../utils';
 import type { observerParam, MutationBufferParam } from '../types';
 import {
@@ -181,13 +182,13 @@ function initMoveObserver({
           ? evt.changedTouches[0]
           : evt;
         if (!timeBaseline) {
-          timeBaseline = Date.now();
+          timeBaseline = nowTimestamp();
         }
         positions.push({
           x: clientX,
           y: clientY,
           id: mirror.getId(target as Node),
-          timeOffset: Date.now() - timeBaseline,
+          timeOffset: nowTimestamp() - timeBaseline,
         });
         // it is possible DragEvent is undefined even on devices
         // that support event 'drag'

packages/rrweb/src/utils.ts

@@ -168,6 +168,15 @@ export function patch(
   }
 }
 
+// guard against old third party libraries which redefine Date.now
+let nowTimestamp = Date.now;
+
+if (!(/*@__PURE__*/ /[1-9][0-9]{12}/.test(Date.now().toString()))) {
+  // they have already redefined it! use a fallback
+  nowTimestamp = () => new Date().getTime();
+}
+export { nowTimestamp };
+
 export function getWindowScroll(win: Window) {
   const doc = win.document;
   return {