1714913 - Get rid of `EditorBase::mPaddingBRElementForEmptyEditor`

Status: NEW

(Core :: DOM: Editor, enhancement, P3)

Description

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

I think that we don't need to keep using mPaddingBRElementForEmptyEditor for both TextEditor and HTMLEditor because:

1. If TextEditor allows empty text node to be a child of anonymous <div>, the padding <br> element is not required (IIRC, the caret position issue has gone).
2. If HTMLEditor, it's created only for empty <br> element, and never created for contenteditable. This causes some different behaviors between designMode and contenteditable.
3. Even if we create the padding <br> element, it can be managed with checking first child of the editing host and flag of the <br> element.

Comment 1

[Kagami Rosylight [:saschanaz] (they/them)]

It turns out designMode=on still needs a padding <br> or data:text/html,<script>document.designMode="on"</script> does not show the caret at all. So I'd like to remove mPaddingBRElementForEmptyEditor only from TextEditor first, what do you think? (Probably in a different bug.)

Note that doing so won't affect <textarea> since currently EnsurePaddingBRElementInMultilineEditor() still want to insert <br> regardless of emptiness. A check could be added but it could cause inconsistency since nothing removes this type of <br> after insertion. (A textarea would be initialized without <br> but then get a permanent one that never disappears even when it becomes empty.)

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

(In reply to Kagami :saschanaz from comment #1)

It turns out designMode=on still needs a padding <br> or data:text/html,<script>document.designMode="on"</script> does not show the caret at all. So I'd like to remove mPaddingBRElementForEmptyEditor only from TextEditor first, what do you think? (Probably in a different bug.)

Sounds reasonable.

Note that doing so won't affect <textarea> since currently EnsurePaddingBRElementInMultilineEditor() still want to insert <br> regardless of emptiness. A check could be added but it could cause inconsistency since nothing removes this type of <br> after insertion. (A textarea would be initialized without <br> but then get a permanent one that never disappears even when it becomes empty.)

Yeah, unfortunately, we need a <br> element at least when there is a last line which is empty. So, I don't think that we can stop using <br> element, but stopping managing the mPaddingBRelementForEmptyEditor as a member may make the code simpler and more stateless since like HTMLEditor, once we failed to handle it, checking the member breaks something.