公式块处理有问题

[TankNee]

$$
X_3^2
$$

会变成

$$
X\_3^2
$$

[vincentbel]

@TankNee 方便提个 PR 修一下？

[rxliuli]

添加 remark-math 插件支持正确解析，然后还必须处理 InlineMath 的问题，解析之后该插件就无法正常工作了，例如

中文$123$中文

格式化之后期待的是

中文 $123$ 中文

但实际上如果添加了 remark-math 插件就会导致类似下面的这种 AST，还必须单独查找并处理

root[1] (1:1-1:10, 0-9)
└─0 paragraph[3] (1:1-1:10, 0-9)
    ├─0 text "中文" (1:1-1:3, 0-2)
    ├─1 inlineMath "123" (1:3-1:8, 2-7)
    │     data: {"hName":"code","hProperties":{"className":["language-math","math-inline"]},"hChildren":[{"type":"text","value":"123"}]}
    └─2 text "中文" (1:8-1:10, 7-9)

添加一个额外的插件解决，晚点吾辈看看是否能给 remark-pangu 提个 PR 修一下

import { visitParents } from 'unist-util-visit-parents'
import * as cjk from 'cjk-regex'
import { Parent, Text } from 'mdast'
import { Plugin } from 'unified'

function spacingInlineMath(): Plugin {
  const CJK_PATTERN = cjk.all().toRegExp()
  return () => {
    return (root, file, next) => {
      visitParents(root, 'inlineMath', (node, ancestors) => {
        const parent = ancestors[ancestors.length - 1] as Parent
        const index = parent.children.indexOf(node as any)
        if (
          parent.children[index - 1] &&
          parent.children[index - 1].type === 'text'
        ) {
          const prev = parent.children[index - 1] as Text
          if (CJK_PATTERN.test(prev.value.slice(-1))) {
            prev.value = prev.value + ' '
          }
        }
        if (
          parent.children[index + 1] &&
          parent.children[index + 1].type === 'text'
        ) {
          const next = parent.children[index + 1] as Text
          if (CJK_PATTERN.test(next.value.slice(0, 1))) {
            next.value = ' ' + next.value
          }
        }
      })
      next(undefined, root, file)
    }
  }
}