fix: reset fns when when stopping record

[wfk007]

reset wrappedEmit and takeFullSnapshot when stopping record

rrweb/packages/rrweb/src/record/index.ts

Line 528 in 5f59f91

record.addCustomEvent = <T>(tag: string, payload: T) => {

rrweb/packages/rrweb/src/record/index.ts

Line 547 in 5f59f91

record.takeFullSnapshot = (isCheckout?: boolean) => {

[Juice10]

This doesn't reset the fns to their original state, this removes the functions

[wfk007]

This doesn't reset the fns to their original state, this removes the functions

These two fns(wrappedEmit and takeFullSnapshot ) are undefined when record is not invoked

In record.addCustomEvent and record.takeFullSnapshot:
Determine whether it is recording by judging whether wrappedEmit or takeFullSnapshot is falsy

[wfk007]

In the below case:

import { record } from "rrweb"

// start record
const stopRecord = record({
  emit: xxx,
})

// stopRecord
stopRecord()

// still invoke 
record.addCustomEvent()
record.takeFullSnapshot()

[Juice10]

Good catch @wfk007, thanks for finding this and clarifying!

[Juice10]

Good catch @wfk007, thanks for finding this and clarifying!

[Yuyz0112]

Thanks!

[Vadman97]

Hi @wfk007 ! After this change, we've noticed that when calling the stop recording callback, observers are not immediately stopped throw the following error:

rrweb/packages/rrweb/src/record/index.ts

Lines 561 to 566 in 2286c11

	return () => {
	handlers.forEach((h) => h());
	// reset init fns when stopping record
	(wrappedEmit as unknown) = undefined;
	(takeFullSnapshot as unknown) = undefined;
	};

Could the mousemoveCb call from the mouse / viewport observers be trying to call wrappedEmit which is set undefined by this PR?

rrweb/packages/rrweb/src/record/observer.ts

Line 157 in 2286c11

mousemoveCb(

[wfk007]

Hi @wfk007 ! After this change, we've noticed that when calling the stop recording callback, observers are not immediately stopped throw the following error:

rrweb/packages/rrweb/src/record/index.ts

Lines 561 to 566 in 2286c11

	return () => {
	handlers.forEach((h) => h());
	// reset init fns when stopping record
	(wrappedEmit as unknown) = undefined;
	(takeFullSnapshot as unknown) = undefined;
	};

Could the mousemoveCb call from the mouse / viewport observers be trying to call wrappedEmit which is set undefined by this PR?

rrweb/packages/rrweb/src/record/observer.ts

Line 157 in 2286c11

mousemoveCb(

@Vadman97 thx for your reply. I encounterred this error too.
It is because that the MoveObserver uses double throttle to track mouseMove events
The first one is updatePosition with options trailing false
the second one is wrappedCb WITHOUT options trailing false
which means that the second throttle will be triggerred async
when stopping record, wrappedEmit will be reset to undefined, but wrappedCb will still execute because of trailing: true

[YunFeng0817]

@wfk007 I encountered this error as well. Do you have any idea or plan to fix this?

[wfk007]

I have come up with three ways to fix this uncaught error

1. rollback this PR but we can not catch record.addCustomEvent() after stopping record
2. using wrappedCb with trailing: false but it will lose last mouseMove positions after stopping record
3. add falsy check for wrappedEmit but it seems stupid

@Yuyz0112 @Juice10 @Mark-Fenng Hi all, any ideas for this uncaught error

[wfk007]

@wfk007 I encountered this error as well. Do you have any idea or plan to fix this?

@Mark-Fenng @Yuyz0112 @Juice10 @Vadman97 I opened a PR to fix this error: #1034