fix(core): check if pos is valid before resolving in backspace core keymap handler

[solastley]

Please describe your changes

So I'm working on a TipTap editor where I don't want to allow block elements in the document. Not exactly a common use case I'm guessing, but it makes sense for what I'm doing.

I discovered that when I override the content of the Document extension to only allow text like so...

Document.extend({
    content: 'text*',
})

...it causes an error to be thrown whenever I press Backspace and either:

1. The editor is empty OR
2. All of the text is selected with the anchor at the beginning of the text

The error comes from the backspace keyboard shortcut handler which is added in TipTap core. This handler attempts to resolve a position in the document at pos - 1 where pos is equal to editor.state.selection.$anchor.pos. I think this works fine when there are block elements in the editor since even an empty editor will still have at least an empty block element. Whenever only text is allowed, though, this pos is equal to zero whenever the editor is empty. This results in the handler attempting to resolve the position in the document at a pos of -1, which throws an error.

How did you accomplish your changes

Added a check that pos > 0 before attempting to resolve pos - 1 in the document.

How have you tested your changes

Tested both cases where I found the error manually, and with this check, the error no longer occurs.

I also tested backspace in a more typical editor configuration with the default Document extension. Everything works as expected, including backspace when there is a lot of text, backspace when there is no text, and backspace when all text is selected.

How can we verify your changes

To reproduce bug:

1. Create an editor and extend Document as I've outlined above.
2. Press Backspace when the editor is empty
3. See the error

To verify fix, repeat the process with my changes applied and see the error is gone.

Remarks

Loving TipTap so far :)

Checklist

• The changes are not breaking the editor
• Added tests where possible
• Followed the guidelines
• Fixed linting issues

Related issues

N/A

[netlify]

✅ Deploy Preview for tiptap-embed ready!

Name	Link
🔨 Latest commit	e79bde0
🔍 Latest deploy log	https://app.netlify.com/sites/tiptap-embed/deploys/65b8c2c0e32c1f0008762f36
😎 Deploy Preview	https://deploy-preview-4835--tiptap-embed.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[bdbch]

LGTM - @svenadlung any thoughts on this?

[alexmalev]

Please describe your changes

So I'm working on a TipTap editor where I don't want to allow block elements in the document. Not exactly a common use case I'm guessing, but it makes sense for what I'm doing.

I discovered that when I override the content of the Document extension to only allow text like so...

Document.extend({
    content: 'text*',
})

...it causes an error to be thrown whenever I press Backspace and either:

1. The editor is empty OR
2. All of the text is selected with the anchor at the beginning of the text

The error comes from the backspace keyboard shortcut handler which is added in TipTap core. This handler attempts to resolve a position in the document at pos - 1 where pos is equal to editor.state.selection.$anchor.pos. I think this works fine when there are block elements in the editor since even an empty editor will still have at least an empty block element. Whenever only text is allowed, though, this pos is equal to zero whenever the editor is empty. This results in the handler attempting to resolve the position in the document at a pos of -1, which throws an error.

How did you accomplish your changes

Added a check that pos > 0 before attempting to resolve pos - 1 in the document.

How have you tested your changes

Tested both cases where I found the error manually, and with this check, the error no longer occurs.

I also tested backspace in a more typical editor configuration with the default Document extension. Everything works as expected, including backspace when there is a lot of text, backspace when there is no text, and backspace when all text is selected.

How can we verify your changes

To reproduce bug:

1. Create an editor and extend Document as I've outlined above.
2. Press Backspace when the editor is empty
3. See the error

To verify fix, repeat the process with my changes applied and see the error is gone.

Remarks

Loving TipTap so far :)

Checklist

• The changes are not breaking the editor
• Added tests where possible
• Followed the guidelines
• Fixed linting issues

Related issues

N/A

very much waiting for this. same exact problem. thanks!

[solastley]

@svenadlung gentle bump