cinny/src/util/markdown.js
ginnyTheCat a8f374dd43
Parsing HTML to Markdown AST (#847)
* Force mentions to have a space after the #

* Use types for rendering

* Parse HTML

* Add code block support

* Add table support

* Allow starting heading without a space

* Escape relevant plaintext areas

* Resolve many crashes

* Use better matrix id regex

* Don't match . after id

* Don't parse mentions as links

* Add emote support

* Only emit HTML link if necessary

* Implement review changes
2022-09-16 21:21:53 +05:30

499 lines
14 KiB
JavaScript

/* eslint-disable no-use-before-define */
import SimpleMarkdown from '@khanacademy/simple-markdown';
import { idRegex, parseIdUri } from './common';
const {
defaultRules, parserFor, outputFor, anyScopeRegex, blockRegex, inlineRegex,
sanitizeText, sanitizeUrl,
} = SimpleMarkdown;
function htmlTag(tagName, content, attributes, isClosed) {
let s = '';
Object.entries(attributes || {}).forEach(([k, v]) => {
if (v !== undefined) {
s += ` ${sanitizeText(k)}`;
if (v !== null) s += `="${sanitizeText(v)}"`;
}
});
s = `<${tagName}${s}>`;
if (isClosed === false) {
return s;
}
return `${s}${content}</${tagName}>`;
}
function mathHtml(wrap, node) {
return htmlTag(wrap, htmlTag('code', sanitizeText(node.content)), { 'data-mx-maths': node.content });
}
const emojiRegex = /^:([\w-]+):/;
const plainRules = {
Array: {
...defaultRules.Array,
plain: defaultRules.Array.html,
},
userMention: {
order: defaultRules.em.order - 0.9,
match: inlineRegex(idRegex('@', undefined, '^')),
parse: (capture, _, state) => ({
type: 'mention',
content: state.userNames[capture[1]] ? `@${state.userNames[capture[1]]}` : capture[1],
id: capture[1],
}),
},
roomMention: {
order: defaultRules.em.order - 0.8,
match: inlineRegex(idRegex('#', undefined, '^')),
parse: (capture) => ({ type: 'mention', content: capture[1], id: capture[1] }),
},
mention: {
plain: (node, _, state) => (state.kind === 'edit' ? node.id : node.content),
html: (node) => htmlTag('a', sanitizeText(node.content), {
href: `https://matrix.to/#/${encodeURIComponent(node.id)}`,
}),
},
emoji: {
order: defaultRules.em.order - 0.1,
match: (source, state) => {
if (!state.inline) return null;
const capture = emojiRegex.exec(source);
if (!capture) return null;
const emoji = state.emojis.get(capture[1]);
if (emoji) return capture;
return null;
},
parse: (capture, _, state) => ({ content: capture[1], emoji: state.emojis.get(capture[1]) }),
plain: ({ emoji }) => (emoji.mxc
? `:${emoji.shortcode}:`
: emoji.unicode),
html: ({ emoji }) => (emoji.mxc
? htmlTag('img', null, {
'data-mx-emoticon': null,
src: emoji.mxc,
alt: `:${emoji.shortcode}:`,
title: `:${emoji.shortcode}:`,
height: 32,
}, false)
: emoji.unicode),
},
newline: {
...defaultRules.newline,
plain: () => '\n',
},
paragraph: {
...defaultRules.paragraph,
plain: (node, output, state) => `${output(node.content, state)}\n\n`,
html: (node, output, state) => htmlTag('p', output(node.content, state)),
},
br: {
...defaultRules.br,
match: anyScopeRegex(/^ *\n/),
plain: () => '\n',
},
text: {
...defaultRules.text,
match: anyScopeRegex(/^[\s\S]+?(?=[^0-9A-Za-z\s\u00c0-\uffff]| *\n|\w+:\S|$)/),
plain: (node) => node.content.replace(/(\*|_|!\[|\[|\|\||\$\$?)/g, '\\$1'),
},
};
const markdownRules = {
...defaultRules,
...plainRules,
heading: {
...defaultRules.heading,
match: blockRegex(/^ *(#{1,6})([^\n:]*?(?: [^\n]*?)?)#* *(?:\n *)+\n/),
plain: (node, output, state) => {
const out = output(node.content, state);
if (state.kind === 'edit' || state.kind === 'notification' || node.level > 2) {
return `${'#'.repeat(node.level)} ${out}\n\n`;
}
return `${out}\n${(node.level === 1 ? '=' : '-').repeat(out.length)}\n\n`;
},
},
hr: {
...defaultRules.hr,
plain: () => '---\n\n',
},
codeBlock: {
...defaultRules.codeBlock,
plain: (node) => `\`\`\`${node.lang || ''}\n${node.content}\n\`\`\``,
html: (node) => htmlTag('pre', htmlTag('code', sanitizeText(node.content), {
class: node.lang ? `language-${node.lang}` : undefined,
})),
},
fence: {
...defaultRules.fence,
match: blockRegex(/^ *(`{3,}|~{3,}) *(?:(\S+) *)?\n([\s\S]+?)\n?\1 *(?:\n *)*\n/),
},
blockQuote: {
...defaultRules.blockQuote,
plain: (node, output, state) => `> ${output(node.content, state).trim().replace(/\n/g, '\n> ')}\n\n`,
},
list: {
...defaultRules.list,
plain: (node, output, state) => `${node.items.map((item, i) => {
const prefix = node.ordered ? `${node.start + i}. ` : '* ';
return prefix + output(item, state).replace(/\n/g, `\n${' '.repeat(prefix.length)}`);
}).join('\n')}\n`,
},
def: undefined,
table: {
...defaultRules.table,
plain: (node, output, state) => {
const header = node.header.map((content) => output(content, state));
const colWidth = node.align.map((align) => {
switch (align) {
case 'left':
case 'right':
return 2;
case 'center':
return 3;
default:
return 1;
}
});
header.forEach((s, i) => {
if (s.length > colWidth[i])colWidth[i] = s.length;
});
const cells = node.cells.map((row) => row.map((content, i) => {
const s = output(content, state);
if (colWidth[i] === undefined || s.length > colWidth[i]) {
colWidth[i] = s.length;
}
return s;
}));
function pad(s, i) {
switch (node.align[i]) {
case 'right':
return s.padStart(colWidth[i]);
case 'center':
return s
.padStart(s.length + Math.floor((colWidth[i] - s.length) / 2))
.padEnd(colWidth[i]);
default:
return s.padEnd(colWidth[i]);
}
}
const line = colWidth.map((len, i) => {
switch (node.align[i]) {
case 'left':
return `:${'-'.repeat(len - 1)}`;
case 'center':
return `:${'-'.repeat(len - 2)}:`;
case 'right':
return `${'-'.repeat(len - 1)}:`;
default:
return '-'.repeat(len);
}
});
const table = [
header.map(pad),
line,
...cells.map((row) => row.map(pad))];
return table.map((row) => `| ${row.join(' | ')} |\n`).join('');
},
},
displayMath: {
order: defaultRules.table.order + 0.1,
match: blockRegex(/^ *\$\$ *\n?([\s\S]+?)\n?\$\$ *(?:\n *)*\n/),
parse: (capture) => ({ content: capture[1] }),
plain: (node) => (node.content.includes('\n')
? `$$\n${node.content}\n$$\n`
: `$$${node.content}$$\n`),
html: (node) => mathHtml('div', node),
},
shrug: {
order: defaultRules.escape.order - 0.1,
match: inlineRegex(/^¯\\_\(ツ\)_\/¯/),
parse: (capture) => ({ type: 'text', content: capture[0] }),
},
escape: {
...defaultRules.escape,
plain: (node, output, state) => `\\${output(node.content, state)}`,
},
tableSeparator: {
...defaultRules.tableSeparator,
plain: () => ' | ',
},
link: {
...defaultRules.link,
plain: (node, output, state) => {
const out = output(node.content, state);
const target = sanitizeUrl(node.target) || '';
if (out !== target || node.title) {
return `[${out}](${target}${node.title ? ` "${node.title}"` : ''})`;
}
return out;
},
html: (node, output, state) => {
const out = output(node.content, state);
const target = sanitizeUrl(node.target) || '';
if (out !== target || node.title) {
return htmlTag('a', out, {
href: target,
title: node.title,
});
}
return target;
},
},
image: {
...defaultRules.image,
plain: (node) => `![${node.alt}](${sanitizeUrl(node.target) || ''}${node.title ? ` "${node.title}"` : ''})`,
html: (node) => htmlTag('img', '', {
src: sanitizeUrl(node.target) || '',
alt: node.alt,
title: node.title,
}, false),
},
reflink: undefined,
refimage: undefined,
em: {
...defaultRules.em,
plain: (node, output, state) => `_${output(node.content, state)}_`,
},
strong: {
...defaultRules.strong,
plain: (node, output, state) => `**${output(node.content, state)}**`,
},
u: {
...defaultRules.u,
plain: (node, output, state) => `__${output(node.content, state)}__`,
},
del: {
...defaultRules.del,
plain: (node, output, state) => `~~${output(node.content, state)}~~`,
},
inlineCode: {
...defaultRules.inlineCode,
plain: (node) => `\`${node.content}\``,
},
spoiler: {
order: defaultRules.inlineCode.order + 0.1,
match: inlineRegex(/^\|\|([\s\S]+?)\|\|(?:\(([\s\S]+?)\))?/),
parse: (capture, parse, state) => ({
content: parse(capture[1], state),
reason: capture[2],
}),
plain: (node, output, state) => {
const warning = `spoiler${node.reason ? `: ${node.reason}` : ''}`;
switch (state.kind) {
case 'edit':
return `||${output(node.content, state)}||${node.reason ? `(${node.reason})` : ''}`;
case 'notification':
return `<${warning}>`;
default:
return `[${warning}](${output(node.content, state)})`;
}
},
html: (node, output, state) => htmlTag(
'span',
output(node.content, state),
{ 'data-mx-spoiler': node.reason || null },
),
},
inlineMath: {
order: defaultRules.del.order + 0.2,
match: inlineRegex(/^\$(\S[\s\S]+?\S|\S)\$(?!\d)/),
parse: (capture) => ({ content: capture[1] }),
plain: (node) => `$${node.content}$`,
html: (node) => mathHtml('span', node),
},
};
function mapElement(el) {
switch (el.tagName) {
case 'MX-REPLY':
return [];
case 'P':
return [{ type: 'paragraph', content: mapChildren(el) }];
case 'BR':
return [{ type: 'br' }];
case 'H1':
case 'H2':
case 'H3':
case 'H4':
case 'H5':
case 'H6':
return [{ type: 'heading', level: Number(el.tagName[1]), content: mapChildren(el) }];
case 'HR':
return [{ type: 'hr' }];
case 'PRE': {
let lang;
if (el.firstChild) {
Array.from(el.firstChild.classList).some((c) => {
const langPrefix = 'language-';
if (c.startsWith(langPrefix)) {
lang = c.slice(langPrefix.length);
return true;
}
return false;
});
}
return [{ type: 'codeBlock', lang, content: el.innerText }];
}
case 'BLOCKQUOTE':
return [{ type: 'blockQuote', content: mapChildren(el) }];
case 'UL':
return [{ type: 'list', items: mapChildren(el) }];
case 'OL':
return [{
type: 'list',
ordered: true,
start: Number(el.getAttribute('start')),
items: mapChildren(el),
}];
case 'TABLE': {
const headerEl = Array.from(el.querySelector('thead > tr').childNodes);
const align = headerEl.map((childE) => childE.style['text-align']);
return [{
type: 'table',
header: headerEl.map(mapChildren),
align,
cells: Array.from(el.querySelectorAll('tbody > tr')).map((rowEl) => Array.from(rowEl.childNodes).map((childEl, i) => {
if (align[i] === undefined) align[i] = childEl.style['text-align'];
return mapChildren(childEl);
})),
}];
}
case 'A': {
const href = el.getAttribute('href');
const id = parseIdUri(href);
if (id) return [{ type: 'mention', content: el.innerText, id }];
return [{
type: 'link',
target: el.getAttribute('href'),
title: el.getAttribute('title'),
content: mapChildren(el),
}];
}
case 'IMG': {
const src = el.getAttribute('src');
let title = el.getAttribute('title');
if (el.hasAttribute('data-mx-emoticon')) {
if (title.length > 2 && title.startsWith(':') && title.endsWith(':')) {
title = title.slice(1, -1);
}
return [{
type: 'emoji',
content: title,
emoji: {
mxc: src,
shortcode: title,
},
}];
}
return [{
type: 'image',
alt: el.getAttribute('alt'),
target: src,
title,
}];
}
case 'EM':
case 'I':
return [{ type: 'em', content: mapChildren(el) }];
case 'STRONG':
case 'B':
return [{ type: 'strong', content: mapChildren(el) }];
case 'U':
return [{ type: 'u', content: mapChildren(el) }];
case 'DEL':
case 'STRIKE':
return [{ type: 'del', content: mapChildren(el) }];
case 'CODE':
return [{ type: 'inlineCode', content: el.innerText }];
case 'DIV':
if (el.hasAttribute('data-mx-maths')) {
return [{ type: 'displayMath', content: el.getAttribute('data-mx-maths') }];
}
return mapChildren(el);
case 'SPAN':
if (el.hasAttribute('data-mx-spoiler')) {
return [{ type: 'spoiler', reason: el.getAttribute('data-mx-spoiler'), content: mapChildren(el) }];
}
if (el.hasAttribute('data-mx-maths')) {
return [{ type: 'inlineMath', content: el.getAttribute('data-mx-maths') }];
}
return mapChildren(el);
default:
return mapChildren(el);
}
}
function mapNode(n) {
switch (n.nodeType) {
case Node.TEXT_NODE:
return [{ type: 'text', content: n.textContent }];
case Node.ELEMENT_NODE:
return mapElement(n);
default:
return [];
}
}
function mapChildren(n) {
return Array.from(n.childNodes).reduce((ast, childN) => {
ast.push(...mapNode(childN));
return ast;
}, []);
}
function render(content, state, plainOut, htmlOut) {
let c = content;
if (content.length === 1 && content[0].type === 'paragraph') {
c = c[0].content;
}
const plainStr = plainOut(c, state).trim();
if (state.onlyPlain) return { plain: plainStr };
const htmlStr = htmlOut(c, state);
const plainHtml = htmlStr.replace(/<br>/g, '\n').replace(/<\/p><p>/g, '\n\n').replace(/<\/?p>/g, '');
const onlyPlain = sanitizeText(plainStr) === plainHtml;
return {
onlyPlain,
plain: plainStr,
html: htmlStr,
};
}
const plainParser = parserFor(plainRules);
const plainPlainOut = outputFor(plainRules, 'plain');
const plainHtmlOut = outputFor(plainRules, 'html');
const mdParser = parserFor(markdownRules);
const mdPlainOut = outputFor(markdownRules, 'plain');
const mdHtmlOut = outputFor(markdownRules, 'html');
export function plain(source, state) {
return render(plainParser(source, state), state, plainPlainOut, plainHtmlOut);
}
export function markdown(source, state) {
return render(mdParser(source, state), state, mdPlainOut, mdHtmlOut);
}
export function html(source, state) {
const el = document.createElement('template');
el.innerHTML = source;
return render(mapChildren(el.content), state, mdPlainOut, mdHtmlOut);
}