client/src/app/core/renderer/markdown.service.ts

   1 import * as MarkdownIt from 'markdown-it'
   2 import { buildVideoLink } from 'src/assets/player/utils'
   3 import { Injectable } from '@angular/core'
   4 import {
   5   COMPLETE_RULES,
   6   ENHANCED_RULES,
   7   ENHANCED_WITH_HTML_RULES,
   8   TEXT_RULES,
   9   TEXT_WITH_HTML_RULES
  10 } from '@shared/core-utils/renderer/markdown'
  11 import { HtmlRendererService } from './html-renderer.service'
  12
  13 type MarkdownParsers = {
  14   textMarkdownIt: MarkdownIt
  15   textWithHTMLMarkdownIt: MarkdownIt
  16
  17   enhancedMarkdownIt: MarkdownIt
  18   enhancedWithHTMLMarkdownIt: MarkdownIt
  19
  20   completeMarkdownIt: MarkdownIt
  21 }
  22
  23 type MarkdownConfig = {
  24   rules: string[]
  25   html: boolean
  26   escape?: boolean
  27 }
  28
  29 type MarkdownParserConfigs = {
  30   [id in keyof MarkdownParsers]: MarkdownConfig
  31 }
  32
  33 @Injectable()
  34 export class MarkdownService {
  35   private markdownParsers: MarkdownParsers = {
  36     textMarkdownIt: null,
  37     textWithHTMLMarkdownIt: null,
  38     enhancedMarkdownIt: null,
  39     enhancedWithHTMLMarkdownIt: null,
  40     completeMarkdownIt: null
  41   }
  42   private parsersConfig: MarkdownParserConfigs = {
  43     textMarkdownIt: { rules: TEXT_RULES, html: false },
  44     textWithHTMLMarkdownIt: { rules: TEXT_WITH_HTML_RULES, html: true, escape: true },
  45
  46     enhancedMarkdownIt: { rules: ENHANCED_RULES, html: false },
  47     enhancedWithHTMLMarkdownIt: { rules: ENHANCED_WITH_HTML_RULES, html: true, escape: true },
  48
  49     completeMarkdownIt: { rules: COMPLETE_RULES, html: true }
  50   }
  51
  52   private emojiModule: any
  53
  54   constructor (private htmlRenderer: HtmlRendererService) {}
  55
  56   textMarkdownToHTML (markdown: string, withHtml = false, withEmoji = false) {
  57     if (withHtml) return this.render('textWithHTMLMarkdownIt', markdown, withEmoji)
  58
  59     return this.render('textMarkdownIt', markdown, withEmoji)
  60   }
  61
  62   enhancedMarkdownToHTML (markdown: string, withHtml = false, withEmoji = false) {
  63     if (withHtml) return this.render('enhancedWithHTMLMarkdownIt', markdown, withEmoji)
  64
  65     return this.render('enhancedMarkdownIt', markdown, withEmoji)
  66   }
  67
  68   completeMarkdownToHTML (markdown: string) {
  69     return this.render('completeMarkdownIt', markdown, true)
  70   }
  71
  72   async processVideoTimestamps (html: string) {
  73     return html.replace(/((\d{1,2}):)?(\d{1,2}):(\d{1,2})/g, function (str, _, h, m, s) {
  74       const t = (3600 * +(h || 0)) + (60 * +(m || 0)) + (+(s || 0))
  75       const url = buildVideoLink({ startTime: t })
  76       return `<a class="video-timestamp" href="${url}">${str}</a>`
  77     })
  78   }
  79
  80   private async render (name: keyof MarkdownParsers, markdown: string, withEmoji = false) {
  81     if (!markdown) return ''
  82
  83     const config = this.parsersConfig[ name ]
  84     if (!this.markdownParsers[ name ]) {
  85       this.markdownParsers[ name ] = await this.createMarkdownIt(config)
  86
  87       if (withEmoji) {
  88         if (!this.emojiModule) {
  89           this.emojiModule = (await import('markdown-it-emoji/light')).default
  90         }
  91
  92         this.markdownParsers[ name ].use(this.emojiModule)
  93       }
  94     }
  95
  96     let html = this.markdownParsers[ name ].render(markdown)
  97     html = this.avoidTruncatedTags(html)
  98
  99     if (config.escape) return this.htmlRenderer.toSafeHtml(html)
 100
 101     return html
 102   }
 103
 104   private async createMarkdownIt (config: MarkdownConfig) {
 105     // FIXME: import('...') returns a struct module, containing a "default" field
 106     const MarkdownItClass: typeof import ('markdown-it') = (await import('markdown-it') as any).default
 107
 108     const markdownIt = new MarkdownItClass('zero', { linkify: true, breaks: true, html: config.html })
 109
 110     for (const rule of config.rules) {
 111       markdownIt.enable(rule)
 112     }
 113
 114     this.setTargetToLinks(markdownIt)
 115
 116     return markdownIt
 117   }
 118
 119   private setTargetToLinks (markdownIt: MarkdownIt) {
 120     // Snippet from markdown-it documentation: https://github.com/markdown-it/markdown-it/blob/master/docs/architecture.md#renderer
 121     const defaultRender = markdownIt.renderer.rules.link_open || function (tokens, idx, options, env, self) {
 122       return self.renderToken(tokens, idx, options)
 123     }
 124
 125     markdownIt.renderer.rules.link_open = function (tokens, index, options, env, self) {
 126       const token = tokens[index]
 127
 128       const targetIndex = token.attrIndex('target')
 129       if (targetIndex < 0) token.attrPush([ 'target', '_blank' ])
 130       else token.attrs[targetIndex][1] = '_blank'
 131
 132       const relIndex = token.attrIndex('rel')
 133       if (relIndex < 0) token.attrPush([ 'rel', 'noopener noreferrer' ])
 134       else token.attrs[relIndex][1] = 'noopener noreferrer'
 135
 136       // pass token to default renderer.
 137       return defaultRender(tokens, index, options, env, self)
 138     }
 139   }
 140
 141   private avoidTruncatedTags (html: string) {
 142     return html.replace(/\*\*?([^*]+)$/, '$1')
 143       .replace(/<a[^>]+>([^<]+)<\/a>\s*...((<\/p>)|(<\/li>)|(<\/strong>))?$/mi, '$1...')
 144       .replace(/\[[^\]]+\]\(([^\)]+)$/m, '$1')
 145       .replace(/\s?\[[^\]]+\]?[.]{3}<\/p>$/m, '...</p>')
 146   }
 147 }