80 lines
2.3 KiB
TypeScript
80 lines
2.3 KiB
TypeScript
import { Injectable } from '@angular/core'
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import * as MarkdownIt from 'markdown-it'
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@Injectable()
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export class MarkdownService {
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static TEXT_RULES = [
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'linkify',
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'autolink',
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'emphasis',
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'link',
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'newline',
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'list'
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]
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static ENHANCED_RULES = MarkdownService.TEXT_RULES.concat([ 'image' ])
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private textMarkdownIt: MarkdownIt.MarkdownIt
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private enhancedMarkdownIt: MarkdownIt.MarkdownIt
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constructor () {
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this.textMarkdownIt = this.createMarkdownIt(MarkdownService.TEXT_RULES)
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this.enhancedMarkdownIt = this.createMarkdownIt(MarkdownService.ENHANCED_RULES)
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}
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textMarkdownToHTML (markdown: string) {
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if (!markdown) return ''
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const html = this.textMarkdownIt.render(markdown)
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return this.avoidTruncatedTags(html)
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}
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enhancedMarkdownToHTML (markdown: string) {
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if (!markdown) return ''
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const html = this.enhancedMarkdownIt.render(markdown)
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return this.avoidTruncatedTags(html)
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}
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private createMarkdownIt (rules: string[]) {
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const markdownIt = new MarkdownIt('zero', { linkify: true, breaks: true })
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for (let rule of rules) {
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markdownIt.enable(rule)
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}
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this.setTargetToLinks(markdownIt)
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return markdownIt
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}
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private setTargetToLinks (markdownIt: MarkdownIt.MarkdownIt) {
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// Snippet from markdown-it documentation: https://github.com/markdown-it/markdown-it/blob/master/docs/architecture.md#renderer
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const defaultRender = markdownIt.renderer.rules.link_open || function (tokens, idx, options, env, self) {
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return self.renderToken(tokens, idx, options)
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}
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markdownIt.renderer.rules.link_open = function (tokens, index, options, env, self) {
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const token = tokens[index]
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const targetIndex = token.attrIndex('target')
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if (targetIndex < 0) token.attrPush([ 'target', '_blank' ])
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else token.attrs[targetIndex][1] = '_blank'
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const relIndex = token.attrIndex('rel')
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if (relIndex < 0) token.attrPush([ 'rel', 'noopener noreferrer' ])
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else token.attrs[relIndex][1] = 'noopener noreferrer'
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// pass token to default renderer.
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return defaultRender(tokens, index, options, env, self)
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}
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}
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private avoidTruncatedTags (html: string) {
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return html.replace(/\*\*?([^*]+)$/, '$1')
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.replace(/<a[^>]+>([^<]+)<\/a>\s*...((<\/p>)|(<\/li>)|(<\/strong>))?$/mi, '$1...')
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.replace(/\[[^\]]+\]?\(?([^\)]+)$/, '$1')
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}
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}
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