Not possible to use Block Indent Feature with custom headings

[antoniolucasnobar]

📝 Provide detailed reproduction steps (if any)

1. Create custom header as defined in Headings page.
2. install block indentation plugin, as stated in its page
3. Select the custom the created custom header
4. Try to use the indent feature

✔️ Expected result

I exptect to be able to use the block indent feature with Custom Headers

❌ Actual result

Both buttons are never enabled, so I can not use this feature

📃 Other details

Looking into the source, I saw the indent block feature only enable itself to knownElements:

// Enable block indentation by default in paragraph and default headings.
const knownElements = [ 'paragraph', 'heading1', 'heading2', 'heading3', 'heading4', 'heading5', 'heading6' ];

This way, we can not use this feature with any custom Headers.

A simple change can allow that. Changing the above line to:

// Enable block indentation by default in paragraph and default headings.
const options = editor.config.get( 'heading.options' );
const headings = options.map(option => option.model);
const knownElements = headings || [ 'paragraph', 'heading1', 'heading2', 'heading3', 'heading4', 'heading5', 'heading6' ];

and voilá, block indent works for all defined headers. Another option would be to have a config option, but I think it would only to double the config between headers and blockindent.

Maybe we do not need the last line, once the headings plugin always set the heading options. But if the user remove the heading plugin, I do not know the results of that.

Please, let me know if this is the way to fix this. I can make a PR, if you folks approve it. If not, please tell me what should be the solution

• Browser: Firefox 80.0
• OS: Linux mint 19.3
• CKEditor version: 22.0
• Installed CKEditor plugins: Essentials, Alignment, Paragraph, Heading, List, Bold, Italic, Indent, Outdent

As a final note, the link to see the code at the end of the contribute section of block indent feature is pointing to the font plugin, not the indent plugin.

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[Mgsy]

Hi, indeed, custom headings are not supported by the indent block feature, as heading elements are hardcoded. Your solution seems to be a good direction, so it would be great if you could prepare a PR with fix and tests, our team will be happy to review it. Thank you for your contribution!

[antoniolucasnobar]

Hello @Mgsy
the PR is ready for someone to look at it.

I do not know to whom should I send the signed CLA. Could you help me with this?

And if you need anything to change in the PR, please let me know.

Best Regards.

[antoniolucasnobar]

CLA e-signed.

[Mgsy]

CLA e-signed.

Great, thanks! We will review your PR soon :)