fix($core): transpile vuepress packages and md files (close #1606)(close #1990)

[meteorlxy]

Summary

Related to #1771

Fix #1606

Fix #1990

Before

// WRONG
/(@vuepress|vuepress-)\/^((?!node_modules).)*\.js$/.test('/a/b/@vuepress/core/lib/index.js')
// false

// CORRECT
/(@vuepress|vuepress-)\/^((?!node_modules).)*\.js$/.test('/a/b/@vuepress/core/node_modules/xxx/index.js')
// false

// WRONG
/(@vuepress|vuepress-)\/^((?!node_modules).)*\.js$/.test('/a/b/vuepress-plugin-xxx/lib/index.js')
// false

// CORRECT
/(@vuepress|vuepress-)\/^((?!node_modules).)*\.js$/.test('/a/b/vuepress-plugin-xxx/node_modules/xxx/index.js')
// false

After

// CORRECT
/(@vuepress\/[^\/]*|vuepress-[^\/]*)\/(?!node_modules).*\.js$/.test('/a/b/@vuepress/core/lib/index.js')
// true

// CORRECT
/(@vuepress\/[^\/]*|vuepress-[^\/]*)\/(?!node_modules).*\.js$/.test('/a/b/@vuepress/core/node_modules/xxx/index.js')
// false

// CORRECT
/(@vuepress\/[^\/]*|vuepress-[^\/]*)\/(?!node_modules).*\.js$/.test('/a/b/vuepress-plugin-xxx/lib/index.js')
// true

// CORRECT
/(@vuepress\/[^\/]*|vuepress-[^\/]*)\/(?!node_modules).*\.js$/.test('/a/b/vuepress-plugin-xxx/node_modules/xxx/index.js')
// false

cc @sodatea

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe:

If changing the UI of default theme, please provide the before/after screenshot:

Does this PR introduce a breaking change? (check one)

• Yes
• No

[kefranabg]

Nice 👍 Would be cool to have an extra review from @sodatea and @ulivz

[mariofriz]

This solves the transpilation issue but it doesn't work on Windows because of \ instead of / for folder separators.

I adapted the regex expression to make it work.

// transpile all core files
if (/(@vuepress[\/\\][^\/\\]*|vuepress-[^\/\\]*)[\/\\](?!node_modules).*\.js$/.test(filePath)) {
  return false
}

@meteorlxy

[meteorlxy]

@mariofriz Thanks for catching this. I'll update it.