client/src/app/videos/shared/markdown.service.ts

   1 import { Injectable } from '@angular/core'
   2
   3 import * as MarkdownIt from 'markdown-it'
   4
   5 @Injectable()
   6 export class MarkdownService {
   7   private markdownIt: MarkdownIt.MarkdownIt
   8
   9   constructor () {
  10     this.markdownIt = new MarkdownIt('zero', { linkify: true, breaks: true })
  11       .enable('linkify')
  12       .enable('autolink')
  13       .enable('emphasis')
  14       .enable('link')
  15       .enable('newline')
  16       .enable('list')
  17
  18     this.setTargetToLinks()
  19   }
  20
  21   markdownToHTML (markdown: string) {
  22     const html = this.markdownIt.render(markdown)
  23
  24     // Avoid linkify truncated links
  25     return html.replace(/<a[^>]+>([^<]+)<\/a>\s*...(<\/p>)?$/mi, '$1...')
  26   }
  27
  28   private setTargetToLinks () {
  29     // Snippet from markdown-it documentation: https://github.com/markdown-it/markdown-it/blob/master/docs/architecture.md#renderer
  30     const defaultRender = this.markdownIt.renderer.rules.link_open || function (tokens, idx, options, env, self) {
  31       return self.renderToken(tokens, idx, options)
  32     }
  33
  34     this.markdownIt.renderer.rules.link_open = function (tokens, idx, options, env, self) {
  35       // If you are sure other plugins can't add `target` - drop check below
  36       const aIndex = tokens[idx].attrIndex('target')
  37
  38       if (aIndex < 0) {
  39         tokens[idx].attrPush(['target', '_blank']) // add new attribute
  40       } else {
  41         tokens[idx].attrs[aIndex][1] = '_blank'    // replace value of existing attr
  42       }
  43
  44       // pass token to default renderer.
  45       return defaultRender(tokens, idx, options, env, self)
  46     }
  47   }
  48 }