Block library: When pressing enter on empty line new Paragraph blocks is crated

[gziolo]

Description

This is an experiment. I have no idea if the solution is the most expected but it does what I want.

This PR mirrors the behavior of List block where pressing enter on empty line removes it and it creates new Paragraph block and moves focus there. I'd love to have it replicated for the following blocks:

• Image (caption)
• Quote (cite)
• Pullquote (cite)
• Preformatted
• Verse

This is how List block works in master:

How has this been tested?

• Add Verse block and start typing.
• Press enter key, a new line should be created.
• Press enter key again, this new line should be removed, new Paragraph block added and focus should move there.

Screenshots

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[gziolo]

I guess, it's buggy but it's enough to get feedback :)

[jasmussen]

To me, this makes a ton of sense on a high level. I'm pinging @ellatrix because I know she has tonnes of thoughts on this also. I recall her mentioning that there was a good reason why the caption didn't work this way — perhaps because you should be able to create a multi-paragraph caption?

[ellatrix]

I think something like this would be good. I once started a PR (#14143) that looked to do something similar.

In general, I like the idea that you should be able to Enter out of every rich text field, but the expectation differ across blocks.

For paragraphs and headings, Enter should always create a new paragraph block.
Perhaps we can do the same for captions and other single line instances. You could still press Shift+Enter to create soft line breaks. Depends on the kind of thing you're building.
For multiline instances, we'd require Enter to be pressed when on an empty line.

[jasmussen]

For multiline instances, we'd require Enter to be pressed when on an empty line.

👍 👍👌

[gziolo]

For paragraphs and headings, Enter should always create a new paragraph block.
Perhaps we can do the same for captions and other single line instances. You could still press Shift+Enter to create soft line breaks. Depends on the kind of thing you're building.
For multiline instances, we'd require Enter to be pressed when on an empty line.

It's exactly what I was thinking about myself. In particular Enter on the empty line was my main motivator to open this PR.

@ellatrix - do you still think, this should be exposed as a new prop of RichText? Ideally, it should be something simple to use so block authors wouldn't have to bother whether you can insert Paragraph in the given context or whether you can insert any block in the first place. I'm thinking about nested blocks in particular where the default behavior might not work as expected. I guess, other behaviors like splitting text blocks are sensitive to that issue as well though.

[ellatrix]

Ideally, it should be something simple to use so block authors wouldn't have to bother whether you can insert Paragraph in the given context or whether you can insert any block in the first place.

Currently this is already the case though. Both the heading and list block insert a paragraph block explicitly. The way I see it, we need an extra prop, because onSplit in already used in single line instances to split on Enter anywhere in the text. And what we want here for verse is the option to split when pressing Enter on an empty line, but it's not a multiline instance like list and quote.

[mapk]

This feels really good! I know I've run into this issue while in the Quote block several times. I hit Enter and it just keeps adding more lines to the Quote. I'd love Gutenberg to recognize the blank line and drop me out of the Quote block and into a Paragraph block.

But I also see the value of being able to hit Shift + Enter to stay within the block no matter how many blank lines are there. Will this option still remain?

[ellatrix]

I've implemented split for the quote block in #17121.

[gziolo]

I'm closing this exploration. We definitely should continue working on the changes in the experience.

[ellatrix]

I've been working towards achieving this with onSplit. I'll have a look into that again soon.