React-dnd: Crashing in isOver with empty targetId

Created on 7 Mar 2019 · 7Comments · Source: react-dnd/react-dnd

Describe the bug
I have a connected drop target that is removed from the DOM, once something is dropped on to it.

Now since upgrading to v7.1.0, I'm getting

Uncaught TypeError: Cannot read property '0' of undefined

in the monitor.isOver() call inside the collect function.
Somehow, it sees that the collect function is still called one more time, after the drop target has been removed (targetId is undefined).

Interesting

Downgrading back to 6.0.0 resolved the issue.
Also, using a short setTimeout wrapper around my callback that removed the drop target, resolved the issue.

Any idea what could cause that?

To Reproduce
Steps to reproduce the behavior:

Connect a Drop target, call monitor.isOver() in collect
in the target, dispatch an action inside drop(...) that removes the drop target
See error

Expected behavior
There is no timing issue with isOver and drop targets can be immediately removed.

Screenshots
bildschirmfoto 2019-03-07 um 00 58 04

Desktop (please complete the following information):

OS: os x
Browser chrome
react-dnd / html5 backend 7.1.0

Source

Kadrian

👍3

Most helpful comment

This should be fixed by cfrank's PR in a release today

darthtrevino on 7 Mar 2019

👍3

All 7 comments

Same issue

RaoHai on 7 Mar 2019

I tried to revert this change https://github.com/react-dnd/react-dnd/commit/0feb250b7ee90483e31f3bc159ebf946980d53a7#diff-ac418ba19283aec1fb0b70e6570c5613 and resolved.. .

RaoHai on 7 Mar 2019

Same issue.
Waiting for fix.
Rolled back to v7.0.2

safonoi on 7 Mar 2019

Confirmed we are receiving the same issue - Reverting to 7.0.2 fixes the issue

cfrank on 7 Mar 2019

This is being caused because the change at 0feb250b7ee90483e31f3bc159ebf946980d53a7 is allowing target ID to be undefined but nobody checked the PR with that change for isOverTarget

Currently it's prototype is:

public isOverTarget(targetId: string, options = { shallow: false })

unlike the other functions which changed in that pr which move targetId / sourceId to

targetId: string | undefined
sourceId: string | undefined

and check: