#️⃣ Hash emoji causes errors in title.

[PatelN123]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Prerequisites

• I'm using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages.
• I have tried creating a repro with https://new.docusaurus.io.
• I have read the console error message carefully (if applicable).

Description

The #️⃣ emoji causes errors.
When using the hash emoji as a title (# #️⃣ text) in a page at the beginning, it uses the ID of the page as the title instead.

Steps to reproduce

1. Create a new docusaurus page
2. Set the title to something with the #️⃣
3. Build the site, the title will be the ID rather than what you specified with the title you specified under it.

Expected behavior

Put the correct title

Actual behavior

Already written ^^

Your environment

• Public source code: https://github.com/PatelN123/Digital-Support-Notes
• Public site URL: https://notes.nayanpatel.net/
• Docusaurus version used: Canary Release

Reproducible demo

No response

Self-service

• I'd be willing to fix this bug myself.

[Josh-Cena]

I figured it out. #️⃣ actually includes # as its first character (because emojis are just a sequence of UTF-16 characters).

String.fromCharCode('#️⃣'.charCodeAt(0))
// << '#'
/#/.test('#️⃣')
// << true

Therefore, our title-parsing regex actually sees:

/(?<pattern>#\s*(?<title>[^#\n{]*)+[ \t]*(?<suffix>({#*[\w-]+})|#)?\n*?)/.exec('# #️⃣ Support')

// << (5) ['# #', '# #', '', '#', undefined, index: 0, input: '# #️⃣ Support', groups: {pattern: '# #', title: '', suffix: '#'}]

This would, once again, be solved once we use Remark for Markdown parsing. ref #5659.

[PatelN123]

Ah yes!
I did think this would be the cause but I didn't know how to explain it.

Thanks!