Heading: Uncaught TypeError when pressing Enter

[mcsf]

Issue Overview

When pressing Enter in a Heading block, either at the end of the editable field or anywhere before that, an uncaught TypeError is thrown, though seemingly no user-facing breakage occurs.

Steps to Reproduce (for bugs)

0. Open the browser console.
1. Start a post.
2. Type ## This is a heading, which should convert to a H2-level Heading.
3. Press Enter to start a Paragraph below.

Expected Behavior

Nothing should happen aside from a new Paragraph appearing and the cursor (and focus) moving to it.

Current Behavior

On the top of the expected behavior, a logged TypeError appears in the console.

Possible Solution

A quick glance at the stack trace and some reading of blocks/editable/index.js make me wonder if this is caused by an interaction in/with TinyMCE. Perhaps @ephox-mogran knows.

Screenshots / Video

Todos

• Tests
• Documentation

[ephox-mogran]

The problem is that the enter key handling is firing on an editor that has just been removed from the dom. If you include a stopImmediatePropagation in the onKeyDown code in editable/index.js, it doesn't happen.

} else {
				event.preventDefault();
                                // This line is added.
				event.stopImmediatePropagation();

				if ( event.shiftKey || ! this.props.onSplit ) {
					this.editor.execCommand( 'InsertLineBreak', false, event );
				} else {
					this.splitContent();
				}
			}

Note, you may only want to add it if you aren't pressing Shift because you really only want to add it when you are recreating the editors. E.g.

} else {
				event.preventDefault();
				if ( event.shiftKey || ! this.props.onSplit ) {
					this.editor.execCommand( 'InsertLineBreak', false, event );
				} else {
                                       // This line is added.
	           		       event.stopImmediatePropagation();

					this.splitContent();
				}
			}

This should stop the caret handling that happens onKeyDown which is causing this problem. It is trying to read the range of an editor no longer in the DOM.

[mcsf]

Thanks for the comment, @ephox-mogran. I've opened a fix.