[RUMF-848] fix last RRWeb issues

* Replace unnecessary RegExp constructor with a regexp value
* Disable the rule on 'mutationBuffer', as I want to remove this in the
future.
* Remove unused `freezePage` function

Author: BenoitZugmeyer

packages/rum-recorder/src/domain/rrweb-snapshot/snapshot.ts

@@ -12,7 +12,7 @@ import {
   SlimDOMOptions,
 } from './types'
 
-const tagNameRegex = RegExp('[^a-z1-6-_]')
+const tagNameRegex = /[^a-z1-6-_]/
 
 export const IGNORED_NODE = -2
 

packages/rum-recorder/src/domain/rrweb/observer.ts

@@ -39,6 +39,8 @@ import {
   throttle,
 } from './utils'
 
+// TODO: remove this global MutationBuffer instance
+// eslint-disable-next-line local-rules/enforce-declarative-modules
 export const mutationBuffer = new MutationBuffer()
 
 function initMutationObserver(

packages/rum-recorder/src/domain/rrweb/record.ts

@@ -6,7 +6,7 @@ import { getWindowHeight, getWindowWidth, mirror, on } from './utils'
 
 let wrappedEmit!: (record: RawRecord, isCheckout?: boolean) => void
 
-function record(options: RecordOptions = {}): RecordAPI {
+export function record(options: RecordOptions = {}): RecordAPI {
   const {
     emit,
     checkoutEveryNms,
@@ -269,9 +269,3 @@ function record(options: RecordOptions = {}): RecordAPI {
     takeFullSnapshot,
   }
 }
-
-record.freezePage = () => {
-  mutationBuffer.freeze()
-}
-
-export { record }