Bold and strikethrough do not work when it's not an isolated word and has punctuation inside

[taoky]

Subject of the issue

Bold (**) and strikethrought (~~) sometimes won't work properly when:

• It is a non-isolated word.
• There are (unicode) punctuation at the beginning or the end of the word inside ** / ~~

Your environment

• OS: macOS 10.14.6
• Packages:
  • remark 13.0.0
  • remark-gfm 1.0.0
  • remark-html 13.0.1
• Env:
  • node 16.5.0
  • npm 7.19.1

Steps to reproduce

test.md:

测试~~（删除线）~~

测试 ~~（删除线）~~

Test~~(StrikeThrough)~~

测试，**粗体。**字符。

测试，**粗体。** 字符。

Test,**bold.**Character.

test.mjs

import remark from 'remark'
import gfm from 'remark-gfm'
import html from 'remark-html'
import fs from 'fs'

remark().use(gfm).use(html).process(fs.readFileSync("./test.md")).then(v => console.log(v.contents))

and node test.mjs

Expected behavior

It outputs:

<p>测试<del>（删除线）</del></p>
<p>测试 <del>（删除线）</del></p>
<p>Test<del>(StrikeThrough)</del></p>
<p>测试，<strong>粗体。</strong>字符。</p>
<p>测试，<strong>粗体。</strong> 字符。</p>
<p>Test,<strong>bold.</strong>Character.</p>

Actual behavior

<p>测试~~（删除线）~~</p>
<p>测试 <del>（删除线）</del></p>
<p>Test~~(StrikeThrough)~~</p>
<p>测试，**粗体。**字符。</p>
<p>测试，<strong>粗体。</strong> 字符。</p>
<p>Test,**bold.**Character.</p>

[Christian Murphy]

The current behavior matches the standard.

You can see it matches github

---

测试~~（删除线）~~

测试 （删除线）

Test~~(StrikeThrough)~~

测试，**粗体。**字符。

测试，粗体。 字符。

Test,**bold.**Character.

---

And where it is documented in the standards

https://spec.commonmark.org/0.30/#example-351
https://spec.commonmark.org/0.30/#example-352
https://github.github.com/gfm/#strikethrough-extension-

You are welcome to suggest a change to the standard https://talk.commonmark.org/

But in the meantime, it makes sense for remark gfm, to implement gfm 🙂