@liuli-util/markdown-util

Markdown encapsulation tool that provides all the functions needed to process Markdown based on mdast. It is recommended to use astexplorer to view the structure of mdast.

fromMarkdown

Converts Markdown to mdast, supports automatic parsing of YAML metadata.

import { fromMarkdown } from '@liuli-util/markdown-util'

const md = `
# Title
This is a paragraph
`.trim()
const mdast = fromMarkdown(md)
console.log(mdast)

toMarkdown

Converts mdast to Markdown.

import { toMarkdown } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
const md = toMarkdown(mdast)
console.log(md)

mdToHast

Converts mdast to hast. Hast is a syntax tree that represents HTML AST. This function converts the syntax tree of Markdown to the syntax tree of HTML.

import { mdToHast } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
const hast = mdToHast(mdast)
console.log(hast)

hastToHtml

Converts hast to html.

import { hastToHtml } from '@liuli-util/markdown-util'

const hast = {
  type: 'root',
  children: [
    {
      type: 'element',
      tagName: 'h1',
      properties: {},
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'element',
      tagName: 'p',
      properties: {},
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
const html = hastToHtml(hast)
console.log(html)

visit

Traverse mdast, supports modifying nodes.

import { visit } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
visit(mdast, (node) => {
  if (node.type === 'heading') {
    node.depth = 2
  }
})
console.log(mdast)

getYamlMeta

Get YAML metadata from mdast.

import { getYamlMeta } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'yaml',
      value: 'title: Title\n',
    },
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
const res = getYamlMeta(mdast)
console.log(res) // { title: 'Title' }

setYamlMeta

Set YAML metadata in mdast.

import { setYamlMeta } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
setYamlMeta(mdast, { title: 'Title' })
console.log(mdast)

flatMap

Map an ast tree, nodes can be deleted or added.

import { flatMap } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
flatMap(mdast, (node) => {
  if (node.type === 'heading') {
    return [
      {
        type: 'paragraph',
        children: [{ type: 'text', value: 'This is a paragraph' }],
      },
    ]
  }
  return [node]
})
console.log(mdast)

If an empty array [] is returned, the node will be deleted.

import { flatMap } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
flatMap(mdast, (node) => {
  if (node.type === 'heading') {
    return []
  }
  return [node]
})
console.log(mdast)

select

Select nodes in mdast.

import { select } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
const res = select(mdast, 'heading')
console.log(res)

selectAll

Select all nodes in mdast.

import { selectAll } from '@liuli-util/markdown-util'

const mdast = {
  type: 'root',
  children: [
    {
      type: 'heading',
      depth: 1,
      children: [{ type: 'text', value: 'Title' }],
    },
    {
      type: 'paragraph',
      children: [{ type: 'text', value: 'This is a paragraph' }],
    },
  ],
}
const res = selectAll(mdast, 'heading')
console.log(res)