forked from Mirrors/elk
351 lines
9.1 KiB
TypeScript
351 lines
9.1 KiB
TypeScript
// @unimport-disable
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import type { Emoji } from 'masto'
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import type { Node } from 'ultrahtml'
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import { ELEMENT_NODE, TEXT_NODE, h, parse, render } from 'ultrahtml'
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import { findAndReplaceEmojisInText } from '@iconify/utils'
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import { emojiRegEx, getEmojiAttributes } from '../config/emojis'
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export interface ContentParseOptions {
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emojis?: Record<string, Emoji>
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markdown?: boolean
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replaceUnicodeEmoji?: boolean
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astTransforms?: Transform[]
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}
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const sanitizerBasicClasses = filterClasses(/^(h-\S*|p-\S*|u-\S*|dt-\S*|e-\S*|mention|hashtag|ellipsis|invisible)$/u)
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const sanitizer = sanitize({
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// Allow basic elements as seen in https://github.com/mastodon/mastodon/blob/17f79082b098e05b68d6f0d38fabb3ac121879a9/lib/sanitize_ext/sanitize_config.rb
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br: {},
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p: {},
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a: {
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href: filterHref(),
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class: sanitizerBasicClasses,
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rel: set('nofollow noopener noreferrer'),
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target: set('_blank'),
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},
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span: {
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class: sanitizerBasicClasses,
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},
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// Allow elements potentially created for Markdown code blocks above
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pre: {},
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code: {
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class: filterClasses(/^language-\w+$/),
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},
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})
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const decoder = process.client ? document.createElement('textarea') : null
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export function decodeHtml(text: string) {
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if (!decoder)
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// not available when SSR
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return text
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decoder.innerHTML = text
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return decoder.value
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}
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/**
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* Parse raw HTML form Mastodon server to AST,
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* with interop of custom emojis and inline Markdown syntax
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*/
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export function parseMastodonHTML(
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html: string,
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options: ContentParseOptions = {},
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) {
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const {
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markdown = true,
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replaceUnicodeEmoji = true,
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} = options
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if (markdown) {
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// Handle code blocks
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html = html
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.replace(/>(```|~~~)(\w*)([\s\S]+?)\1/g, (_1, _2, lang: string, raw: string) => {
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const code = htmlToText(raw)
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const classes = lang ? ` class="language-${lang}"` : ''
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return `><pre><code${classes}>${code}</code></pre>`
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})
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}
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// Always sanitize the raw HTML data *after* it has been modified
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const transforms: Transform[] = [
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sanitizer,
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...options.astTransforms || [],
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]
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if (replaceUnicodeEmoji)
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transforms.push(transformUnicodeEmoji)
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if (markdown)
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transforms.push(transformMarkdown)
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transforms.push(replaceCustomEmoji(options.emojis || {}))
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return transformSync(parse(html), transforms)
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}
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/**
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* Converts raw HTML form Mastodon server to HTML for Tiptap editor
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*/
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export function convertMastodonHTML(html: string, customEmojis: Record<string, Emoji> = {}) {
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const tree = parseMastodonHTML(html, {
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emojis: customEmojis,
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markdown: true,
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replaceUnicodeEmoji: false,
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})
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return render(tree)
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}
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export function htmlToText(html: string) {
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const tree = parse(html)
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return (tree.children as Node[]).map(n => treeToText(n)).join('').trim()
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}
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export function treeToText(input: Node): string {
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let pre = ''
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let body = ''
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let post = ''
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if (input.type === TEXT_NODE)
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return decodeHtml(input.value)
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if (input.name === 'br')
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return '\n'
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if (['p', 'pre'].includes(input.name))
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pre = '\n'
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if (input.name === 'code') {
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if (input.parent?.name === 'pre') {
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const lang = input.attributes.class?.replace('language-', '')
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pre = `\`\`\`${lang || ''}\n`
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post = '\n```'
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}
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else {
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pre = '`'
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post = '`'
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}
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}
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else if (input.name === 'b' || input.name === 'strong') {
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pre = '**'
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post = '**'
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}
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else if (input.name === 'i' || input.name === 'em') {
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pre = '*'
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post = '*'
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}
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else if (input.name === 'del') {
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pre = '~~'
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post = '~~'
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}
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if ('children' in input)
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body = (input.children as Node[]).map(n => treeToText(n)).join('')
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if (input.name === 'img') {
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if (input.attributes.class?.includes('custom-emoji'))
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return `:${input.attributes['data-emoji-id']}:`
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if (input.attributes.class?.includes('iconify-emoji'))
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return input.attributes.alt
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}
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return pre + body + post
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}
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// A tree transform function takes an ultrahtml Node object and returns
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// new content that will replace the given node in the tree.
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// Returning a null removes the node from the tree.
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// Strings get converted to text nodes.
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// The input node's children have been transformed before the node itself
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// gets transformed.
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type Transform = (node: Node) => (Node | string)[] | Node | string | null
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// Helpers for transforming (filtering, modifying, ...) a parsed HTML tree
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// by running the given chain of transform functions one-by-one.
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function transformSync(doc: Node, transforms: Transform[]) {
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function visit(node: Node, transform: Transform, isRoot = false) {
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if (Array.isArray(node.children)) {
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const children = [] as (Node | string)[]
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for (let i = 0; i < node.children.length; i++) {
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const result = visit(node.children[i], transform)
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if (Array.isArray(result))
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children.push(...result)
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else if (result)
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children.push(result)
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}
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node.children = children.map((value) => {
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if (typeof value === 'string')
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return { type: TEXT_NODE, value, parent: node }
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value.parent = node
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return value
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})
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}
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return isRoot ? node : transform(node)
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}
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for (const transform of transforms)
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doc = visit(doc, transform, true) as Node
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return doc
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}
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// A tree transform for sanitizing elements & their attributes.
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type AttrSanitizers = Record<string, (value: string | undefined) => string | undefined>
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function sanitize(allowedElements: Record<string, AttrSanitizers>): Transform {
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return (node) => {
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if (node.type !== ELEMENT_NODE)
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return node
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if (!Object.prototype.hasOwnProperty.call(allowedElements, node.name))
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return null
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const attrSanitizers = allowedElements[node.name]
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const attrs = {} as Record<string, string>
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for (const [name, func] of Object.entries(attrSanitizers)) {
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const value = func(node.attributes[name])
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if (value !== undefined)
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attrs[name] = value
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}
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node.attributes = attrs
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return node
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}
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}
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function filterClasses(allowed: RegExp) {
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return (c: string | undefined) => {
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if (!c)
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return undefined
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return c.split(/\s/g).filter(cls => allowed.test(cls)).join(' ')
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}
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}
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function set(value: string) {
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return () => value
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}
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function filterHref() {
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const LINK_PROTOCOLS = new Set([
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'http:',
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'https:',
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'dat:',
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'dweb:',
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'ipfs:',
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'ipns:',
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'ssb:',
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'gopher:',
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'xmpp:',
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'magnet:',
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'gemini:',
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])
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return (href: string | undefined) => {
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if (href === undefined)
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return undefined
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// Allow relative links
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if (href.startsWith('/') || href.startsWith('.'))
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return href
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let url
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try {
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url = new URL(href)
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}
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catch (err) {
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if (err instanceof TypeError)
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return undefined
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throw err
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}
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if (LINK_PROTOCOLS.has(url.protocol))
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return url.toString()
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return '#'
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}
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}
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function transformUnicodeEmoji(node: Node) {
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if (node.type !== TEXT_NODE)
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return node
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let start = 0
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const matches = [] as (string | Node)[]
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findAndReplaceEmojisInText(emojiRegEx, node.value, (match, result) => {
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const attrs = getEmojiAttributes(match)
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matches.push(result.slice(start))
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matches.push(h('img', { src: attrs.src, alt: attrs.alt, class: attrs.class }))
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start = result.length + match.match.length
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return undefined
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})
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if (matches.length === 0)
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return node
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matches.push(node.value.slice(start))
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return matches.filter(Boolean)
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}
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function replaceCustomEmoji(customEmojis: Record<string, Emoji>): Transform {
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return (node) => {
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if (node.type !== TEXT_NODE)
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return node
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const split = node.value.split(/:([\w-]+?):/g)
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if (split.length === 1)
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return node
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return split.map((name, i) => {
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if (i % 2 === 0)
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return name
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const emoji = customEmojis[name]
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if (!emoji)
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return `:${name}:`
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return h('img', { 'src': emoji.url, 'alt': `:${name}:`, 'class': 'custom-emoji', 'data-emoji-id': name })
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}).filter(Boolean)
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}
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}
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const _markdownReplacements: [RegExp, (c: (string | Node)[]) => Node][] = [
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[/\*\*\*(.*?)\*\*\*/g, c => h('b', null, [h('em', null, c)])],
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[/\*\*(.*?)\*\*/g, c => h('b', null, c)],
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[/\*(.*?)\*/g, c => h('em', null, c)],
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[/~~(.*?)~~/g, c => h('del', null, c)],
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[/`([^`]+?)`/g, c => h('code', null, c)],
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]
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function _markdownProcess(value: string) {
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const results = [] as (string | Node)[]
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let start = 0
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while (true) {
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let found: { match: RegExpMatchArray; replacer: (c: (string | Node)[]) => Node } | undefined
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for (const [re, replacer] of _markdownReplacements) {
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re.lastIndex = start
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const match = re.exec(value)
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if (match) {
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if (!found || match.index < found.match.index!)
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found = { match, replacer }
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}
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}
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if (!found)
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break
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results.push(value.slice(start, found.match.index))
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results.push(found.replacer(_markdownProcess(found.match[1])))
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start = found.match.index! + found.match[0].length
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}
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results.push(value.slice(start))
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return results.filter(Boolean)
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}
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function transformMarkdown(node: Node) {
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if (node.type !== TEXT_NODE)
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return node
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return _markdownProcess(node.value)
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}
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