• ⚛️ Drop-in replacement for <TextInput> component
• ⌨️ Live synchronous formatting on every keystroke
• ⚡ Fully native experience (selection, spellcheck, autocomplete)
• 🔧 Customizable logic
• 🎨 Customizable styles
• 🌐 Universal support (Android, iOS, web)
• 🏗️ Supports New Architecture

First, install the library from npm with the package manager of your choice:

yarn add @expensify/react-native-live-markdown react-native-reanimated expensify-common
npm install @expensify/react-native-live-markdown react-native-reanimated expensify-common --save
npx expo install @expensify/react-native-live-markdown react-native-reanimated expensify-common

React Native Live Markdown requires react-native-reanimated 3.16.4 or newer and expensify-common 2.0.108 or newer.

Then, install the iOS dependencies with CocoaPods:

cd ios && bundler install && bundler exec pod install

The library includes native code so you will need to re-build the native app.

import {MarkdownTextInput, parseExpensiMark} from '@expensify/react-native-live-markdown';
import React from 'react';

export default function App() {
  const [text, setText] = React.useState('Hello, *world*!');

  return (
    <MarkdownTextInput
      value={text}
      onChangeText={setText}
      parser={parseExpensiMark}
    />
  );
}

MarkdownTextInput can be styled using style prop just like regular TextInput component.

It is also possible to customize the styling of the formatted contents of MarkdownTextInput component. The style object supports all color representations from React Native including PlatformColor and DynamicColorIOS according to the color reference. Currently, a limited set of styles is customizable but this is subject to change in the future.

import type {MarkdownStyle} from '@expensify/react-native-live-markdown';

const FONT_FAMILY_MONOSPACE = Platform.select({
  ios: 'Courier',
  default: 'monospace',
});

const markdownStyle: MarkdownStyle = {
  syntax: {
    color: 'gray',
  },
  link: {
    color: 'blue',
  },
  h1: {
    fontSize: 25,
  },
  emoji: {
    fontSize: 20,
  },
  blockquote: {
    borderColor: 'gray',
    borderWidth: 6,
    marginLeft: 6,
    paddingLeft: 6,
  },
  code: {
    fontFamily: FONT_FAMILY_MONOSPACE,
    fontSize: 20,
    color: 'black',
    backgroundColor: 'lightgray',
  },
  pre: {
    fontFamily: FONT_FAMILY_MONOSPACE,
    fontSize: 20,
    color: 'black',
    backgroundColor: 'lightgray',
  },
  mentionHere: {
    color: 'green',
    backgroundColor: 'lime',
  },
  mentionUser: {
    color: 'blue',
    backgroundColor: 'cyan',
  },
};

The style object can be passed to multiple MarkdownTextInput components using markdownStyle prop:

<MarkdownTextInput
  value={text}
  onChangeText={setText}
  style={styles.input}
  markdownStyle={markdownStyle}
/>

MarkdownTextInput behavior can be customized via parser property. Parser is a function that accepts a plaintext string and returns an array of MarkdownRange objects:

interface MarkdownRange {
  type: MarkdownType;
  start: number;
  length: number;
  depth?: number;
}

Currently, only the following types are supported:

type MarkdownType = 'bold' | 'italic' | 'strikethrough' | 'emoji' | 'mention-here' | 'mention-user' | 'mention-report' | 'link' | 'code' | 'pre' | 'blockquote' | 'h1' | 'syntax';

Parser needs to be marked as a worklet because it's executed on the UI thread as the user types.

Here's a sample function that parses all substrings located between two asterisks as bold text:

function parser(input: string) {
  'worklet';

  const ranges = [];
  const regexp = /\*(.*?)\*/g;
  let match;
  while ((match = regexp.exec(input)) !== null) {
    ranges.push({start: match.index, length: 1, type: 'syntax'});
    ranges.push({start: match.index + 1, length: match[1]!.length, type: 'bold'});
    ranges.push({start: match.index + 1 + match[1]!.length, length: 1, type: 'syntax'});
  }
  return ranges;
}

Currently, react-native-live-markdown supports only ExpensiMark flavor. We are working on CommonMark support as well as possibility to use other Markdown parsers.

MarkdownTextInput inherits all props of React Native's TextInput component as well as introduces the following properties:

react-native-live-markdown requires React Native 0.75 or newer.

MIT