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

import React from 'react';
import { Text, StyleSheet, ViewPropTypes } from 'react-native';
import PropTypes from 'prop-types';
import EasyMarkdown from 'react-native-easy-markdown'; // eslint-disable-line
import SimpleMarkdown from 'simple-markdown';
import { emojify } from 'react-emojione';
import { connect } from 'react-redux';
import styles from './styles';
import CustomEmoji from '../EmojiPicker/CustomEmoji';

const BlockCode = ({ node, state }) => (
	<Text
		key={state.key}
		style={styles.codeStyle}
	>
		{node.content}
	</Text>
);
const mentionStyle = { color: '#13679a' };

const defaultRules = {
	username: {
		order: -1,
		match: SimpleMarkdown.inlineRegex(/^@[0-9a-zA-Z-_.]+/),
		parse: capture => ({ content: capture[0] }),
		react: (node, output, state) => ({
			type: 'custom',
			key: state.key,
			props: {
				children: (
					<Text
						key={state.key}
						style={mentionStyle}
						onPress={() => alert('Username')}
					>
						{node.content}
					</Text>
				)
			}
		})
	},
	heading: {
		order: -2,
		match: SimpleMarkdown.inlineRegex(/^#[0-9a-zA-Z-_.]+/),
		parse: capture => ({ content: capture[0] }),
		react: (node, output, state) => ({
			type: 'custom',
			key: state.key,
			props: {
				children: (
					<Text
						key={state.key}
						style={mentionStyle}
						onPress={() => alert('Room')}
					>
						{node.content}
					</Text>
				)
			}
		})
	},
	fence: {
		order: -3,
		match: SimpleMarkdown.blockRegex(/^ *(`{3,}|~{3,}) *(\S+)? *\n([\s\S]+?)\s*\1 *(?:\n *)+\n/),
		parse: capture => ({
			lang: capture[2] || undefined,
			content: capture[3]
		}),
		react: (node, output, state) => ({
			type: 'custom',
			key: state.key,
			props: {
				children: (
					<BlockCode key={state.key} node={node} state={state} />
				)
			}
		})
	},
	blockCode: {
		order: -4,
		match: SimpleMarkdown.blockRegex(/^(```)\s*([\s\S]*?[^`])\s*\1(?!```)/),
		parse: capture => ({ content: capture[2] }),
		react: (node, output, state) => ({
			type: 'custom',
			key: state.key,
			props: {
				children: (
					<BlockCode key={state.key} node={node} state={state} />
				)
			}
		})
	}
};

const codeStyle = StyleSheet.flatten(styles.codeStyle);

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

@connect(state => ({
	customEmojis: state.customEmojis
}))
export default class Markdown extends React.Component {
	shouldComponentUpdate(nextProps) {
		return nextProps.msg !== this.props.msg;
	}
	render() {
		const {
			msg, customEmojis = {}, style, markdownStyle, customRules, renderInline
		} = this.props;
		if (!msg) {
			return null;
		}
		let m = formatText(msg);
		m = emojify(m, { output: 'unicode' });

		const s = StyleSheet.flatten(style);
		return (
			<EasyMarkdown
				style={{ marginBottom: 0, ...s }}
				markdownStyles={{ code: codeStyle, ...markdownStyle }}
				rules={{
					customEmoji: {
						order: -5,
						match: SimpleMarkdown.inlineRegex(/^:([0-9a-zA-Z-_.]+):/),
						parse: capture => ({ content: capture }),
						react: (node, output, state) => {
							const element = {
								type: 'custom',
								key: state.key,
								props: {
									children: <Text key={state.key}>{node.content[0]}</Text>
								}
							};
							const content = node.content[1];
							const emojiExtension = customEmojis[content];
							if (emojiExtension) {
								const emoji = { extension: emojiExtension, content };
								element.props.children = (
									<CustomEmoji key={state.key} style={styles.customEmoji} emoji={emoji} />
								);
							}
							return element;
						}
					},
					...defaultRules,
					...customRules
				}}
				renderInline={renderInline}
			>{m}
			</EasyMarkdown>
		);
	}
}

Markdown.propTypes = {
	msg: PropTypes.string,
	customEmojis: PropTypes.object,
	// eslint-disable-next-line react/no-typos
	style: ViewPropTypes.style,
	markdownStyle: PropTypes.object,
	customRules: PropTypes.object,
	renderInline: PropTypes.bool
};

BlockCode.propTypes = {
	node: PropTypes.object,
	state: PropTypes.object
};