fix(watch): memory leak

[yangmingshan]

I think computed have same problem, but unless expose a stop api, I don't think there is an easy way to fix it.

[yyx990803]

Did you run into a real memory leak with this? I think this is actually fine because watch effects are only recorded if watch() is called synchronously within setup(). No new watchers will be recorded after the setup() of the component, therefore the watchers recorded by an instance is deterministic - i.e. it's not possible to have a long-living component that keeps recording an infinitely growing number of watchers.

[yyx990803]

Oh nvm, it's possible with this.$watch.

[yyx990803]

It's ok for computed because there is no API to create instance-bound computed outside of setup().

[yyx990803]

Suggested change

	const index = effects.findIndex(_effect => _effect === effect)
	const index = effects.indexOf(effect)

[yyx990803]

Suggested change

	export function recordEffect(effect: ReactiveEffect): RemoveRecord | void {
	export function recordEffect(effect: ReactiveEffect): (() => void) | void {

[yyx990803]

Suggested change

type RemoveRecord = () => void

[yangmingshan]

No, I didn't run into a real memory leak, I just thought it have risk, actually I didn't think about this.$watch 😂

But this.$watch won't be recorded in effects list right? So, do we need to change the implementation? Can I try?

[yangmingshan]

Forget it, I break KeepAlive tests and I don't know why.