Conflict: Check for dropTargetIds in handleTopDrop()

[chrisbuttery]

This PR is a fix to address issue #32

Check dropTargetIds exists and has a length. If so, do something.

[chrisbuttery]

Hello, I'm just wondering if we could add this conditional to check the existence and length of dropTargetIds.

If it doesn't exists or have and ids, do nothing.

[acusti]

I’ve run into this same issue. It’s very intermittent, and I have no idea what causes handleTopDrop to get invoked when targetIds doesn’t exist, but whatever the cause, the result is we get the Uncaught Invariant Violation: Expected targetIds to be an array error.

@darthtrevino Does the approach in this PR look safe as a way to harden the event handling, even if it doesn’t address the root cause?

[darthtrevino]

This looks like it may be an initial state issue. this.dropTargetIds is never set in the constructor. Would adding this.dropTargetIds = [] to the constructor solve this?

[darthtrevino]

If this issue persists in the newest version, let me know, and we can work a solution out in the monorepo