Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

You may not call monitor.canDrop() inside your canDrop() implementation

See original GitHub issue

In canDrop, before returning false, we want to update state to display notification about why it can’t be dropped, but got this error:

Uncaught Error: You may not call monitor.canDrop() inside your canDrop() implementation. Read more: http://react-dnd.github.io/react-dnd/docs-drop-target-monitor.html

Is there a way to deal with it or may be a callback function?

Issue Analytics

State:
Created 6 years ago
Comments:15 (5 by maintainers)

Top GitHub Comments

2reactions

wuweiweiwucommented, Mar 12, 2018

@zourbuth this issue is confirmed and I think its due to how we bind this when we create DropTarget. I will have to investigate more later

I will consider possibly writing so canDrop to allow a callback. Or possibly passing the same object to onDragStateChanged. Seems to be a tricky issue

1reaction

kohsahcommented, Nov 19, 2019

I did a hacky workaround for this issue, since showing a rejection notification in canDrop() was triggered multiple times, so i got dozens of rejection notifications when only one was neccessary.

so i have a variable in state which just records the last success or failure of canDrop.

then in onDragStateChanged if its not isDragging i check the variable from state, and display the error notif, if it was a failure. For a complete drag action, onDragStateChanged is triggered once so it works.