@Trott

About #43018 (review), I hope we can discuss here.
unwatch(index), not an expression, is implemented internally but undocumented anywhere. Should I add the doc to node help along with the debugger doc or leave it undocumented in terms of internal use only?

If it is clear how to obtain the index and how index differs from expr, and if this would be useful to end users, then we should document it. Thanks.

Removing watcher by index would be useful for end users because watchers command prints all watched expressions with their indices.

However, the current watch(expr) accepts numeric as well as string expression, which makes the difference index and expr ambiguous.
So I think string validation for watch(expr) is required (#42913).

@lpinca @Mesteery @Trott Could you check again and land if there is nothing wrong with.

CI: https://ci.nodejs.org/job/node-test-pull-request/44728/