Why does Quill filter its content?

When I use QuillJs to edit an existing HTML document, it removes the comments, indentations etc of the original HTML. Is there anyway to prevent this?

Quill does not support arbitrary HTML. By default, anything that is not recognized will be converted (the <strong> tag to the <b> tag) when possible, or removed when not.

In Quill configuration options, use the configuration named formats. The formats defined in this property will create a whitelist, where anything not in it will be filtered. A list of all formats can be found here.

For more information, visit the following links:

• Quill JavaScript Rich Text Editor restrict tags
• Suppress certain formats in Quill
• How to use format whitelist in QuillJS?

To add support for new formats you will need to create a new one. See the following links to find out how this can be done:

• What, how and when to use static formats, formats and format on custom blot?
• Cloning Medium with Parchment
• Parchment API
• Native examples
• A emoji blot example

As a tip, if you want to create Blot, and you want to allow it to be only edited or removed as a whole, set your Blot to be a child of Embed.

EDIT (DEC 20, 2019)

I forgot to say something: If you are pasting content to the editor, you better take a look at the clipboard module.