Rocket.Chat.ReactNative/app/containers/message/Markdown.js

import React from 'react';
import { Text, Image } from 'react-native';
import PropTypes from 'prop-types';
import { emojify } from 'react-emojione';
import MarkdownRenderer, { PluginContainer } from 'react-native-markdown-renderer';
import MarkdownFlowdock from 'markdown-it-flowdock';

import styles from './styles';
import CustomEmoji from '../EmojiPicker/CustomEmoji';
import MarkdownEmojiPlugin from './MarkdownEmojiPlugin';
import I18n from '../../i18n';

const EmojiPlugin = new PluginContainer(MarkdownEmojiPlugin);
const MentionsPlugin = new PluginContainer(MarkdownFlowdock);
const plugins = [EmojiPlugin, MentionsPlugin];

// Support <http://link|Text>
const formatText = text => text.replace(
	new RegExp('(?:<|<)((?:https|http):\\/\\/[^\\|]+)\\|(.+?)(?=>|>)(?:>|>)', 'gm'),
	(match, url, title) => `[${ title }](${ url })`
);

const emojiRanges = [
	'\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff]', // unicode emoji from https://www.regextester.com/106421
	':.{1,40}:', // custom emoji
	' |\n' // allow spaces and line breaks
].join('|');

const removeAllEmoji = str => str.replace(new RegExp(emojiRanges, 'g'), '');

const isOnlyEmoji = str => !removeAllEmoji(str).length;

const removeOneEmoji = str => str.replace(new RegExp(emojiRanges), '');

const emojiCount = (str) => {
	let oldLength = 0;
	let counter = 0;

	while (oldLength !== str.length) {
		oldLength = str.length;
		str = removeOneEmoji(str);
		if (oldLength !== str.length) {
			counter += 1;
		}
	}

	return counter;
};

const Markdown = React.memo(({
	msg, style, rules, baseUrl, username, isEdited, numberOfLines, mentions, channels, getCustomEmoji, useMarkdown = true
}) => {
	if (!msg) {
		return null;
	}
	let m = formatText(msg);
	if (m) {
		m = emojify(m, { output: 'unicode' });
	}
	m = m.replace(/^\[([^\]]*)\]\(([^)]*)\)\s/, '').trim();
	if (numberOfLines > 0) {
		m = m.replace(/[\n]+/g, '\n').trim();
	}

	if (!useMarkdown) {
		return <Text style={styles.text} numberOfLines={numberOfLines}>{m}</Text>;
	}

	const isMessageContainsOnlyEmoji = isOnlyEmoji(m) && emojiCount(m) <= 3;

	return (
		<MarkdownRenderer
			rules={{
				paragraph: (node, children) => (
					<Text key={node.key} style={styles.paragraph} numberOfLines={numberOfLines}>
						{children}
						{isEdited ? <Text style={styles.edited}> ({I18n.t('edited')})</Text> : null}
					</Text>
				),
				mention: (node) => {
					const { content, key } = node;
					let mentionStyle = styles.mention;
					if (content === 'all' || content === 'here') {
						mentionStyle = {
							...mentionStyle,
							...styles.mentionAll
						};
					} else if (content === username) {
						mentionStyle = {
							...mentionStyle,
							...styles.mentionLoggedUser
						};
					}
					if (mentions && mentions.length && mentions.findIndex(mention => mention.username === content) !== -1) {
						return (
							<Text style={mentionStyle} key={key}>
								&nbsp;{content}&nbsp;
							</Text>
						);
					}
					return `@${ content }`;
				},
				hashtag: (node) => {
					const { content, key } = node;
					if (channels && channels.length && channels.findIndex(channel => channel.name === content) !== -1) {
						return (
							<Text key={key} style={styles.mention}>
								&nbsp;#{content}&nbsp;
							</Text>
						);
					}
					return `#${ content }`;
				},
				emoji: (node) => {
					if (node.children && node.children.length && node.children[0].content) {
						const { content } = node.children[0];
						const emoji = getCustomEmoji && getCustomEmoji(content);
						if (emoji) {
							return (
								<CustomEmoji
									key={node.key}
									baseUrl={baseUrl}
									style={isMessageContainsOnlyEmoji ? styles.customEmojiBig : styles.customEmoji}
									emoji={emoji}
								/>
							);
						}
						return <Text key={node.key}>:{content}:</Text>;
					}
					return null;
				},
				hardbreak: () => null,
				blocklink: () => null,
				image: node => (
					<Image key={node.key} style={styles.inlineImage} source={{ uri: node.attributes.src }} />
				),
				...rules
			}}
			style={{
				paragraph: styles.paragraph,
				text: isMessageContainsOnlyEmoji ? styles.textBig : styles.text,
				codeInline: styles.codeInline,
				codeBlock: styles.codeBlock,
				link: styles.link,
				...style
			}}
			plugins={plugins}
		>{m}
		</MarkdownRenderer>
	);
}, (prevProps, nextProps) => prevProps.msg === nextProps.msg);

Markdown.propTypes = {
	msg: PropTypes.string,
	username: PropTypes.string,
	baseUrl: PropTypes.string,
	style: PropTypes.any,
	rules: PropTypes.object,
	isEdited: PropTypes.bool,
	numberOfLines: PropTypes.number,
	useMarkdown: PropTypes.bool,
	mentions: PropTypes.oneOfType([PropTypes.array, PropTypes.object]),
	channels: PropTypes.oneOfType([PropTypes.array, PropTypes.object]),
	getCustomEmoji: PropTypes.func
};
Markdown.displayName = 'MessageMarkdown';

export default Markdown;