server/helpers/markdown.ts

   1 import { getDefaultSanitizeOptions, getTextOnlySanitizeOptions, TEXT_WITH_HTML_RULES } from '@shared/core-utils'
   2
   3 const defaultSanitizeOptions = getDefaultSanitizeOptions()
   4 const textOnlySanitizeOptions = getTextOnlySanitizeOptions()
   5
   6 const sanitizeHtml = require('sanitize-html')
   7 const markdownItEmoji = require('markdown-it-emoji/light')
   8 const MarkdownItClass = require('markdown-it')
   9
  10 const markdownItWithHTML = new MarkdownItClass('default', { linkify: true, breaks: true, html: true })
  11 const markdownItWithoutHTML = new MarkdownItClass('default', { linkify: false, breaks: true, html: false })
  12
  13 const toSafeHtml = (text: string) => {
  14   if (!text) return ''
  15
  16   // Restore line feed
  17   const textWithLineFeed = text.replace(/<br.?\/?>/g, '\r\n')
  18
  19   // Convert possible markdown (emojis, emphasis and lists) to html
  20   const html = markdownItWithHTML.enable(TEXT_WITH_HTML_RULES)
  21                                  .use(markdownItEmoji)
  22                                  .render(textWithLineFeed)
  23
  24   // Convert to safe Html
  25   return sanitizeHtml(html, defaultSanitizeOptions)
  26 }
  27
  28 const mdToOneLinePlainText = (text: string) => {
  29   if (!text) return ''
  30
  31   markdownItWithoutHTML.use(markdownItEmoji)
  32                        .use(plainTextPlugin)
  33                        .render(text)
  34
  35   // Convert to safe Html
  36   return sanitizeHtml(markdownItWithoutHTML.plainText, textOnlySanitizeOptions)
  37 }
  38
  39 // ---------------------------------------------------------------------------
  40
  41 export {
  42   toSafeHtml,
  43   mdToOneLinePlainText
  44 }
  45
  46 // ---------------------------------------------------------------------------
  47
  48 // Thanks: https://github.com/wavesheep/markdown-it-plain-text
  49 function plainTextPlugin (markdownIt: any) {
  50   let lastSeparator = ''
  51
  52   function plainTextRule (state: any) {
  53     const text = scan(state.tokens)
  54
  55     markdownIt.plainText = text.replace(/\s+/g, ' ')
  56   }
  57
  58   function scan (tokens: any[]) {
  59     let text = ''
  60
  61     for (const token of tokens) {
  62       if (token.children !== null) {
  63         text += scan(token.children)
  64         continue
  65       }
  66
  67       if (token.type === 'list_item_close') {
  68         lastSeparator = ', '
  69       } else if (token.type.endsWith('_close')) {
  70         lastSeparator = ' '
  71       } else if (token.content) {
  72         text += lastSeparator
  73         text += token.content
  74       }
  75     }
  76
  77     return text
  78   }
  79
  80   markdownIt.core.ruler.push('plainText', plainTextRule)
  81 }