Error in console at link selection

[MikeDevice]

Description

If text contains a link and user tries to select this link, then follow error appears in console
Uncaught TypeError: Array.prototype.forEach called on null or undefined

Steps to reproduce

1. Type some text
2. Create a link at one word
3. Select this link using mouse many times.

Expected behavior:
No errors in console

Actual behavior:
An error message outputs to the console

Link to an example:
JSFiddle

Versions

• medium-editor: 5.21.0
• browser: 51.0.2704.106 (64-bit)
• OS: ubuntu 14.04 LTS

[nmielnik]

Ah, I was finally able to get a repro on this! (thanks @MikeDevice).

Looks like the issue is within events.detachDOMEvent() and potentially events.attachDOMEvent(). We need to safety check to ensure the targets actually exists and is an array. Seems like with the anchor-preview mouse-out detection, there could be a case where we try to detach an event listener from an element that might not exist anymore.

[nmielnik]

You can find more discussion about this same issue as part of #1137