Bruno Lemos

Posted on Mar 6, 2019 • Edited on Dec 11, 2020

Tutorial: How to share code between iOS, Android & Web using React Native, react-native-web and monorepo

#react #reactnative #webdev #javascript

Let's make our react-native app work in the browser, the right way.

This tutorial was made for react-native <= 0.61. If you are using a newer version, I recommend that you fork this repository instead: brunolemos/react-native-web-monorepo, I am keeping it updated 🙌

Why am I writing this?

Hi 👋 I'm Bruno Lemos. I recently launched a project called DevHub - TweetDeck for GitHub and one of the things that caught people's attention was the fact that it is an app made by a single developer and available on 6 platforms: Web (react-native-web), iOS (react native), Android (react native), macOS, Windows and Linux (electron, for now), with almost 100% code sharing between them. It even shares some code with the server! This is something that would require a team of 3+ until a couple years ago.

Since then, I've received dozens of tweets and private messages asking how to achieve the same and in this tutorial I'll walk you through it.

What's `react-native-web`?

If you are not familiar with react-native-web, it's a lib by Necolas (ex Twitter engineer) to make your React Native code render in the browser. Roughly speaking, you will write <View /> and it will render <div />, making sure all styles render the exact same thing. It does more than that, but let's keep it simple.

The new Twitter was created using this technology and it's awesome.

If you already know react-native, you don't need to learn any new syntax. It's the same API.

Summary

Starting a new React Native project
Turning our folder structure into a monorepo
Making react-native work in a monorepo
Sharing code between our monorepo packages
Creating a new web project using create-react-app and react-native-web
Making CRA work inside our monorepo with code sharing
???
Profit

Step-by-step tutorial

Starting a new `React Native` project

$ react-native init myprojectname
$ cd myprojectname
$ git init && git add . -A && git commit -m "Initial commit"

Note: It's much easier to create a cross platform app from scratch than trying to port an existing mobile-only (or even harder: web-only) project, since they may be using lot's of platform specific dependencies.

EDIT: If you use expo, it seems they will soon have built in support for web!

Turning our folder structure into a monorepo

Monorepo means having multiple packages in a single repository so you can easily share code between them. It's a bit less trivial than it sounds because both react-native and create-react-app require some work to support monorepo projects. But hey, at least it's possible!

We'll use a feature called Yarn Workspaces for that.
Requirements: Node.js, Yarn and React Native.

Make sure you are at the project root folder
$ rm yarn.lock && rm -rf node_modules
$ mkdir -p packages/components/src packages/mobile packages/web
Move all the files (except .git) to the packages/mobile folder
Edit the name field on packages/mobile/package.json from packagename to mobile
Create this package.json at the root directory to enable Yarn Workspaces:



{
  "name": "myprojectname",
  "private": true,
  "workspaces": {
    "packages": [
      "packages/*"
    ],
    "nohoist": []
  }
  "dependencies": {
    "react-native": "0.61.3"
  }
}

Create a .gitignore at the root directory:



.DS_Store
.vscode
node_modules/
yarn-error.log

$ yarn

Making react-native work in a monorepo

Check where react-native got installed. If it was at /node_modules/react-native, all right. If it was at /packages/mobile/node_modules/react-native, something is wrong. Make sure you have the latest versions of node and yarn. Also make sure to use the exact same version of dependencies between the monorepo packages, e.g. "react": "16.11.0" on both mobile and components, not a different version between them.
Open your favorite editor and use the Search & Replace feature to replace all occurrences of node_modules/react-native/ with ../../node_modules/react-native/.
For react-native <= 0.59, open packages/mobile/package.json. Your start script currently ends in /cli.js start. Append this to the end: --projectRoot ../../.
Open packages./mobile/metro.config.js and set the projectRoot field on it as well so it looks like this:



const path = require('path')

module.exports = {
  projectRoot: path.resolve(__dirname, '../../'),
  transformer: {
    getTransformOptions: async () => ({
      transform: {
        experimentalImportSupport: false,
        inlineRequires: false,
      },
    }),
  },
}

[Workaround] You currently need to add the react-native dependency to the root package.json to be able to bundle the JS:



  "dependencies": {
    "react-native": "0.61.3"
  },

iOS changes

$ open packages/mobile/ios/myprojectname.xcodeproj/
Open AppDelegate.m, find jsBundleURLForBundleRoot:@"index" and replace index with packages/mobile/index
Still inside Xcode, click on your project name on the left, and then go to Build Phases > Bundle React Native code and Images. Replace its content with this:



export NODE_BINARY=node
export EXTRA_PACKAGER_ARGS="--entry-file packages/mobile/index.js"
../../../node_modules/react-native/scripts/react-native-xcode.sh

$ yarn workspace mobile start

You can now run the iOS app! 💙 Choose one iPhone emulator and press the "Run" triangle button inside Xcode.

Android changes

$ studio packages/mobile/android/
Open packages/mobile/android/app/build.gradle. Search for the text project.ext.react = [...]. Edit it so it looks like this:



project.ext.react = [
    entryFile: "packages/mobile/index.js",
    root: "../../../../"
]

Android Studio will show a Sync Now popup. Click on it.
Open packages/mobile/android/app/src/main/java/com/myprojectname/MainApplication.java. Search for the getJSMainModuleName method. Replace index with packages/mobile/index, so it looks like this:



@Override
protected String getJSMainModuleName() {
  return "packages/mobile/index";
}

If you get the Cannot get property 'packageName' on null object error, try disabling auto linking

You can now run the Android app! 💙 Press the "Run" green triangle button inside Android Studio and choose the emulator or device.

Sharing code between our monorepo packages

We've created lots of folders in our monorepo, but only used mobile so far. Let's prepare our codebase for code sharing and then move some files to the components package, so it can be reused by mobile, web and any other platform we decide to support in the future (e.g.: desktop, server, etc.).

Create the file packages/components/package.json with the following contents:



{
  "name": "components",
  "version": "0.0.1",
  "private": true
}

[optional] If you decide to support more platforms in the future, you'll do the same thing for them: Create a packages/core/package.json, packages/desktop/package.json, packages/server/package.json, etc. The name field must be unique for each one.
Open packages/mobile/package.json. Add all the monorepo packages that you are using as dependencies. In this tutorial, mobile is only using the components package:



"dependencies": {
  "components": "0.0.1",
  ...
}

Stop the react-native packager if it's running
$ yarn
$ mv packages/mobile/App.js packages/components/src/
Open packages/mobile/index.js. Replace import App from './App' with import App from 'components/src/App'. This is the magic working right here. One package now have access to the others!
Edit packages/components/src/App.js, replace Welcome to React Native! with Welcome to React Native monorepo! so we know we are rendering the correct file.
$ yarn workspace mobile start

Yay! You can now refresh the running iOS/Android apps and see our screen that's coming from our shared components package. 🎉

$ git add . -A && git commit -m "Monorepo"

Web project

Note: You can reuse up to 100% of the code, but that doesn't mean you should. It's recommended to have some differences between platforms to make them feel more natural to the user. To do that, you can create platform-specific files ending with .web.js, .ios.js, .android.js or .native.js. See example.

Creating a new web project using CRA and react-native-web

$ cd packages/
$ npx create-react-app web
$ cd ./web (stay inside this folder for the next steps)
$ rm src/* (or manually delete all files inside packages/web/src)
Make sure the dependencies inside package.json are the exact same between all monorepo packages. For example, update the "react" version to "16.9.0" (or any other version) on both web and mobile packages.
$ yarn add react-native-web react-art
$ yarn add --dev babel-plugin-react-native-web
Create the file packages/web/src/index.js with the following contents:



import { AppRegistry } from 'react-native'

import App from 'components/src/App'

AppRegistry.registerComponent('myprojectname', () => App)
AppRegistry.runApplication('myprojectname', {
  rootTag: document.getElementById('root'),
})

Note: when we import from react-native inside a create-react-app project, its webpack config automatically alias it to react-native-web for us.

Create the file packages/web/public/index.css with the following contents:



html,
body,
#root,
#root > div {
  width: 100%;
  height: 100%;
}

body {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

Edit packages/web/public/index.html to include our CSS before closing the head tag:



...
<title>React App</title>
<link rel="stylesheet" href="%PUBLIC_URL%/index.css" />
</head>

Making CRA work inside our monorepo with code sharing

CRA doesn't build files outside the src folder by default. We need to make it do it, so it can understand the code from our monorepo packages, which contains JSX and other non-pure-JS code.

Stay inside packages/web/ for the next steps
Create a .env file (packages/web/.env) with the following content:



SKIP_PREFLIGHT_CHECK=true

$ yarn add --dev react-app-rewired
Replace the scripts inside packages/web/package.json with this:



"scripts": {
  "start": "react-app-rewired start",
  "build": "react-app-rewired build",
  "test": "react-app-rewired test",
  "eject": "react-app-rewired eject"
},

Create the packages/web/config-overrides.js file with the following contents:



const fs = require('fs')
const path = require('path')
const webpack = require('webpack')

const appDirectory = fs.realpathSync(process.cwd())
const resolveApp = relativePath => path.resolve(appDirectory, relativePath)

// our packages that will now be included in the CRA build step
const appIncludes = [
  resolveApp('src'),
  resolveApp('../components/src'),
]

module.exports = function override(config, env) {
  // allow importing from outside of src folder
  config.resolve.plugins = config.resolve.plugins.filter(
    plugin => plugin.constructor.name !== 'ModuleScopePlugin'
  )
  config.module.rules[0].include = appIncludes
  config.module.rules[1] = null
  config.module.rules[2].oneOf[1].include = appIncludes
  config.module.rules[2].oneOf[1].options.plugins = [
    require.resolve('babel-plugin-react-native-web'),
  ].concat(config.module.rules[2].oneOf[1].options.plugins)
  config.module.rules = config.module.rules.filter(Boolean)
  config.plugins.push(
    new webpack.DefinePlugin({ __DEV__: env !== 'production' })
  )

  return config
}

The code above overrides some create-react-app's webpack config so it includes our monorepo packages in CRA's build step

$ git add . -A && git commit -m "Web project"

That's it! You can now run yarn start inside packages/web (or yarn workspace web start at the root directory) to start the web project, sharing code with our react-native mobile project! 🎉

Some gotchas

react-native-web supports most of the react-native API, but a few pieces are missing like Alert, Modal, RefreshControl and WebView;
If you come across a dependency that doesn't work well with the monorepo structure, you may add it to the nohoist list; But avoid that if possible, because it may cause other issues, specially with the metro bundler.

Some tips

Navigation may be a bit of a challenge; you can use something like react-navigation which recently added web support or you can try using two different navigators between and mobile, in case you want the best of both worlds by compromising some code sharing;
If you plan sharing code with the server, I recommend creating a core package that only contain logic and helper functions (no UI-related code);
For Next.js, you can check their official example with react-native-web
For native windows, you can try react-native-windows;
For native macOS, you can the new Apple Project Catalyst, but support for it is not 100% there yet (see my tweet);
To install new dependencies, use the command yarn workspace components add xxx from the root directory. To run a script from a package, run yarn workspace web start, for example; To run a script from all packages, run yarn workspaces run scriptname;

Thanks for reading! 💙

If you like react, consider following me here on Dev.to and on Twitter.

Top comments (158)

bantingGamer • Mar 13 '19

HELP! something changed and i cannot replicate this tutorial anymore. i cannot get past the first time you are testing android studio. I remember something like --version react-native@next that is now missing from this tutorial. and now i cannot replicate it at all some one please help.

this is now the 7th time im following the instructions and i get this error first time i try test in the android simulator after trying to create monorepo

Unable to resolve module `./packages/mobile/index

Bruno Lemos • Mar 13 '19

Hi, I updated the tutorial with the latest changes from react-native@0.59, search for projectRoot to see the updated step involving the file metro.config.js.

bantingGamer • Mar 14 '19

Hey Bruno how are you?

Im still running into a issue. Soon as i complete the web section of the tutorial. my mono repo breaks for mobile. it installs all the modules in packages/mobile/node-modules instead of root/node_modules.

Thus when I run packages/mobile/yarn start i get the following error
"Error: Cannot find module 'E:\2019_PROJECTS\moco-messenger-project\code\repo\test\node_modules\react-native\local-cli\cli.js'"

I dont understand how the web project is affecting the mobile project. Please assist.

kind regards

Bruno Lemos • Mar 14 '19

Make sure you have the correct content inside the root package.json and you used yarn at the root directory to install the dependencies, not inside each package neither npm instead of yarn.

Compare your code with the repository to see if anything is different: github.com/brunolemos/react-native...

bantingGamer • Mar 14 '19

hey bruno,

I just did like you said, I even upgraded react-native to v0.59.0 stable. yet still when i run yarn in the root it still installs packages/mobile/node-modules and not in root/node_modules.

how can i compare an entire project with difference in vs code? are you sure there isnt a step missing? I have tried 3 times now following your exact instructions.

Bruno Lemos • Mar 14 '19

Do you have the latest version of nodejs and yarn? How is your root package.json?

bantingGamer • Mar 14 '19 • Edited

I just checked on my computer, im running yarn 1.130 and node v10.0.0 i believe those are the latest versions.

my root package.json file looks exactly like yours.

{
"name": "myprojectname",
"version": "0.0.1",
"private": true,
"workspaces": {
"packages": [
"packages/*"
]
}
}

like i said im extremely confused becasue i dont understand why the monorepo breaks when i add the web

bantingGamer • Mar 14 '19 • Edited

i just downloaded your project at
github.com/brunolemos/react-native... and when i run yarn in the root it is also installing the packages in the wrong places.

Ryan Atkinson • Mar 16 '19 • Edited

Hey everyone, I downloaded the project, followed the updated tutorial and ran into the same exact issue. I got /mobile running again by updating the relative filepath in its package.json to the react-native-cli:

"scripts": {
    "start": "node ./node_modules/react-native/local-cli/cli.js start",
    "test": "jest"
  },

good luck!

Bruno Lemos • Mar 20 '19 • Edited

Hey, you both were right! React Native started getting installed inside packages/mobile/node_modules, which is wrong. Changing the path is not the right solution though.

I investigated and you need to make sure all your dependencies have the exact same version between the monorepo packages. For example, change your "react" dependency inside the mobile and web's package.json to the exact same version (e.g. 16.8.4).

This will make react-native get installed in the root node_modules again and also prevent multiple instances of react being installed in the same project, which would cause all kinds of bugs.

Updated the tutorial and also the repository: github.com/brunolemos/react-native...

bantingGamer • Mar 13 '19 • Edited

thank you so much for the new changes in the tutorial. i made the changes to the metro.config.js just like you suggested and i can now run it on android. i will continue with the rest of the tutorial in the morning.

Vietnam Travel Bag • May 4 '19

Hi Bruno,

How to use 3rd lib, I want to add react-native-element package.
It's work well on mobile, but when I run web app, it's error below:

Support for the experimental syntax 'classProperties' isn't currently enabled (41:23):

  39 | 
  40 | export default class SwipeRating extends Component {
> 41 |   static defaultProps = {
     |                       ^
  42 |     type: 'star',
  43 |     ratingImage: require('./images/star.png'),
  44 |     ratingColor: '#f1c40f',

Add @babel/plugin-proposal-class-properties (https://git.io/vb4SL) to the 'plugins' section of your Babel config to enable transformation.

Here's what I added to config-override.js on packages/web

const appIncludes = [
  ...
  resolveApp('../../node_modules/react-native-elements'),
  resolveApp('../../node_modules/react-native-vector-icons'),
]

module.exports = function override(config, env) { 
  ...
  config.module.rules[2].oneOf[1].options.plugins = [
    require.resolve('babel-plugin-react-native-web'),
    require.resolve('@babel/plugin-proposal-class-properties'),
  ].concat(config.module.rules[2].oneOf[1].options.plugins)
  ...
}

In future, I will add react-navigation and some other packages.
Please help, many thanks!

Bruno Lemos • Jun 4 '19

Did you make it work?

I haven't tried your code but yes, changing config-override.js correctly should be enough.

Nishant Koli • Jul 15 '19

Was anyone able to add react-navigation to the project? I got react-native-elements working by following the above comment.

Here's a working example for React-Navigation with web :
github.com/react-native-elements/r...

Thank for documenting all this work thoroughly.
As a React-Native noob, this guide was very easy to follow along ! Cheers!

Nishant Koli • Jul 22 '19

I got react-navigation's drawer working on the web.

The following is my config-override.js

const fs = require('fs')
const path = require('path')
const webpack = require('webpack')

const appDirectory = fs.realpathSync(process.cwd())
const resolveApp = relativePath => path.resolve(appDirectory, relativePath)

// our packages that will now be included in the CRA build step
const appIncludes = [
  resolveApp('src'),
  resolveApp('../components/src'),
  resolveApp('../../node_modules/@react-navigation'),
  resolveApp('../../node_modules/react-navigation'),
  resolveApp('../../node_modules/react-native-uncompiled'),
  resolveApp('../../node_modules/react-native-elements'),
  resolveApp('../../node_modules/react-native-gesture-handler'),
  resolveApp('../../node_modules/react-native-ratings'),
  resolveApp('../../node_modules/react-native-screens'),
  resolveApp('../../node_modules/react-native-tab-view'),
  resolveApp('../../node_modules/react-native-vector-icons'),
  resolveApp('../components/libraries/MSALAuthLogin'),
  resolveApp('../../node_modules/react-native-vector-icons'),

]

module.exports = function override(config, env) {
  // allow importing from outside of src folder
  config.resolve.plugins = config.resolve.plugins.filter(
    plugin => plugin.constructor.name !== 'ModuleScopePlugin'
  )
  config.module.rules[0].include = appIncludes
  config.module.rules[1] = null
  config.module.rules[2].oneOf[1].include = appIncludes
  config.module.rules[2].oneOf[1].options.plugins = [
    require.resolve('babel-plugin-react-native-web'),
    require.resolve('@babel/plugin-proposal-class-properties'),
  ].concat(config.module.rules[2].oneOf[1].options.plugins)
  config.module.rules = config.module.rules.filter(Boolean)
  config.plugins.push(
    new webpack.DefinePlugin({ __DEV__: env !== 'production' })
  )

  return config
}

Oz Shemesh • Aug 6 '19 • Edited

thanks for the input
i am facing similar issue while using GoogleSigninButton from react-native-google-signin.

i tried adding require.resolve('@babel/plugin-proposal-class-properties') as you suggested below.

also tried to update babel.config.js with the following, didnt worked as well...
module.exports = {
plugins: [
[
'@babel/plugin-proposal-decorators',
{
legacy: true,
},
],
[
'@babel/plugin-proposal-class-properties',
{
loose: true,
},
],
'@babel/plugin-syntax-dynamic-import',
'@babel/plugin-transform-regenerator',
[
'@babel/plugin-transform-runtime',
{
helpers: false,
regenerator: true,
},
],
],
presets: ['@babel/preset-flow', 'module:metro-react-native-babel-preset'],
}

also tried with loose: true
require.resolve('@babel/plugin-proposal-class-properties', {
loose: true,
}),

any suggestion please?

thanks for you time.

Nishant Koli • Aug 15 '19

Hi Oz, were you able to make it run? Did you try with a compatible release (any before 0.60)?

Oz Shemesh • Aug 16 '19

Hi Nishant,

Unfortunately I was not able to solve it.
I am not sure about earlier versions but I went over many possible suggestions, none of them worked...
Any additional idea that I can try?

Thanks for the reply

Rajendran Nadar • Nov 23 '19

Use this config to fix the issue

config.module.rules.push(
    {
        test: /\.js$/,
        use: {
            loader: 'babel-loader',
            options: {
                // Disable reading babel configuration
                babelrc: false,
                configFile: false,

                // The configration for compilation
                presets: [
                    '@babel/preset-env',
                    '@babel/preset-react',
                    '@babel/preset-flow'
                ],
                plugins: [
                    '@babel/plugin-proposal-class-properties',
                    '@babel/plugin-proposal-object-rest-spread'                  
               ]
            }
        }
    }
)

Add the above code before the return config line

Oz Shemesh • Dec 5 '19

Thanks Rajendran

i tried adding the above as part of config-overrides.js
it didn't helped.

BTW, i`ve executed 'sudo yarn add @react-native-community/google-signin'

Under the folder 'react-native-web-monorepo/packages/components'
Is that the right location?

Thanks, Oz

Oz Shemesh • Dec 5 '19

An update...
i had to add two more dev dependencies under the web module.
sudo yarn add --dev babel-loader
sudo yarn add --dev @babel/preset-flow

now i am getting different error:
/react-native-web-monorepo/node_modules/@react-native-community/google-signin/src/GoogleSigninButton.js
Attempted import error: 'requireNativeComponent' is not exported from 'react-native'.

karvulf • Aug 2 '19 • Edited

With the react-native-version 0.60.4, I have some problems with libhermes.
When starting the android-app, it crashes and I always get the message: E/SoLoader: couldn't find DSO to load: libhermes.so. Any suggestions what to do?

Edit: Fixed my problem. You have to enable hermes, so that it looks like this in your build.gradle in app:
project.ext.react = [
entryFile: "packages/mobile/index.js",
root: "../../../../",
enableHermes: true, // clean and rebuild if changing
]

Rafael Jesus Hernández Vasquez • Jan 9 '20

This works for me thanks!

Shubham Sinha • Mar 7 '19 • Edited

scripts: {
  "start": "node ../../node_modules/react-native/local-cli/cli.js start --projectRoot ../../"
}

throws error error: unknown option `--projectRoot'

On modifying --projectRoot to --projectRoots I get following error

Loading dependency graph...jest-haste-map: Watchman crawl failed. Retrying once with node crawler.

Bruno Lemos • Mar 7 '19 • Edited

You mean when trying to use jest? If not please check the repository to see what you made differently.

Shubham Sinha • Mar 7 '19

Sorry, I modified my comment. I am getting an error with --projectRoot. I was trying on my own repo. I'll be cloning your repo and then let you know if the problem persists.

Bruno Lemos • Mar 7 '19

I'm using the unreleased react-native 0.59 in this tutorial, some dependencies got a major bump so maybe there are some differences if you are using an older version.

AsmaGithub • Jul 29 '19

did you find an alternative for --projectRoot please ?

Zia Ul Rehman • Jul 23 '19

Hi Bruno, thanks for the awesome detailed tutorial with all the updates. And i can see you are very active in comments also which is awesome!

Its really nice to see react's progress towards PWA and cross platform portability.

I am following this tutorial to convert our old add(on Rn 0.59) over to react-native web. I followed this tutorial and setup everything up.
Than i copied the dependencies from our mobile repo's package json to packages/components/package.json. And all other code respectively in src. Idea was to get everything running on ios in this monorepo setup and than go from there to fix whatever needs to be fixed for web.

But i am getting some errors like first i got:

bundling failed: Error: Unable to resolve module path from /Users/..../projec/node_modules/react-native-dotenv/index.js: Module path does not exist in the Haste module map

Fixed it by adding path explicitly in dev-dependencies. Than started getting error:

bundling failed: Error: While trying to resolve module fs from file /Users/..../projec/node_modules/babel-plugin-dotenv/index.js, the package /Users/..../projec/node_modules/fs/package.json was successfully found. However, this package itself specifies a main module field that could not be resolved (/Users/..../projec/node_modules/fs/index.js. Indeed, none of these files exist

I am not very experienced in react and react-native, i am mainly on Ruby on Rails, so maybe this is something basic which i am getting wrong.
I found: stackoverflow.com/a/39046690/4738391 which suggests omething wrong with node environment or something. But i am a bit confused, i mean i can add these dependencies etc but it should work out of the box for mobile, as it was working fine in previous repo.

Any help will be greatly appreciated. Thanks.

Zia Ul Rehman • Jul 25 '19 • Edited

This was a stupid error, i had forgot to add 'module:react-native-dotenv' in my babel config presets. Adding it solved the problem and i got my mobile app compiled. There were some imports fixes etc in scode needed to be done to run app successfully. But that is done.

But now next errors(on web), i posted this SO question: stackoverflow.com/questions/571953...

If i can get any help, would be great.

Zia Ul Rehman • Jul 23 '19

After cache clean and everything, second error changed to:
error: bundling failed: Error: While trying to resolve module fs from file /Users/..../projec/node_modules/babel-plugin-dotenv/index.js, the package /Users/..../projec/node_modules/fs/package.json was successfully found. However, this package itself specifies a main module field that could not be resolved (/Users/..../projec/node_modules/fs/index.js. Indeed, none of these files exist

Colter McQuay • Dec 30 '19

I was running into the same issue and I think I figured out the cause of the problem. I unfortunately don't know how to fix it. It seems to be related to react-native-cli not being able to locate the metro and babel configs because it's being run from the root of the repository.

Since they aren't found, when the bundler comes across react-native-dotenv within a source file it will actually import the source file rather than using the replacement provided by the babel plugin.

Bruno Lemos • Jul 23 '19 • Edited

Please remove all node_modules folders and .lock files from your project, clear all caches (xcode, —reset-cache, etc), and try following the steps again. Maybe you missed something.

You shouldn’t remove the dependencies from mobile. Check this repo source code and commit diffs: github.com/brunolemos/react-native...

After running yarn to install dependencies, check the contents of packages/mobile/node_modules, and let me know which folders it has. It shouldn’t have any, all should be in the root node_modules.

If nothing works, maybe they released a new version of the cli that broke something, in that case you can use a previous version or investigate the change.

Zia Ul Rehman • Jul 23 '19 • Edited

I think i was not clear in my comment, actually it did work with barebone setup as described in this post. It was working perfectly, than i started exporting my mobile code, that's when it exploded.

I wanted to just have mobile app running as it is in this architecture. Than move un-convertable code to mobile and write replacement code for only those in web. But my mobile app is not running with these errors.

I did all the cache clear and everything but same issue. mobile repo's node_modules folder have 2 folder, .bin and metro-react-native-babel-preset.

I am pretty sure it is some of my mobile dependency. I don't know if i should share the package json etc and everything here. It will just get annoyingly long here.

Let me know if i should share that here, or i can reach you through some other medium.

I do understand this blog post is like THE go to blog right now for new projects which want to take this route. but porting old projects is a lot more messy. If i do succeed in porting my app on this architecture and support web, i will leave pointers and can also write an extension of this blog post.

Sergey Pushkin • Mar 26 '19 • Edited

You can run debug session from vscode with React Native Tools extension. But with monorepo its little hacky... btw, read-native run-its --project-path "./packages/mobile/ios" also work

I setup only iOS project with macos: you need to specify "runArguments": ["--project-path", "./packages/mobile/ios"] in debug task in launch.json and symlink with command:

ln -s /Users/proof666/Desktop/Projects/ShopList_new/PaperList/packages/mobile/ios  /Users/proof666/Desktop/Projects/ShopList_new/PaperList/ios

~if somebody already setup android debug, please ping me~
Update:
in vscode task for android add

...
"runArguments": ["--root", "./packages/mobile"]

Bruno Lemos • Mar 27 '19

Thanks for sharing!

Daryl Aranha • Dec 8 '21

I am unable to run android app. When I run yarn android I am getting this error.

FAILURE: Build failed with an exception.

* Where:
Script '<Project Path>/monorepo/node_modules/react-native/react.gradle' line: 34

* What went wrong:
A problem occurred configuring project ':app'.
> Failed to notify project evaluation listener.
   > Couldn't determine CLI location. Please set `project.ext.react.cliPath` to the path of the react-native cli.js

How to update project.ext.react.cliPath path?
Can anyone suggest what changes did I miss?

Daryl Aranha • Dec 9 '21

I found it. Thank you. I needed to add cliPath inside project.ext.react in app/build.gradle

Ahmed Eid • Dec 27 '21

how did you do that, could you please add a screenshot or something ?

Daryl Aranha • Jan 23 '22

I apologies for the late response.
Basically what you need to do is go to mobile/android/app/build.gradle and update the file as show below.

...
project.ext.react = [
    ...
    root: "../../../../",
    cliPath: "../../../../node_modules/react-native"
    ...
]
...

If you want to jump right into the code then you can check out my repo, I have updated the setup.

Comment deleted

Bruno Lemos • Mar 7 '19

Nice, thanks for the mention in the article!

Were you able to share code between web and mobile using nohoist? I've had problems with this approach in the past but I don't remember exactly why. It has some downsides but it's definitely much simpler to setup. Everything working well for you this way?

Zhigang Fang • Apr 19 '19

No, sry for taking so long to reply.

Our yarn workspace is just set up to include app / backend / website

And they do not share components.

The problem is that metro does not support symbol links. Which is what yarn workspace uses.

github.com/facebook/metro/issues/1

Pra3t0r5 • Aug 15 '20

Hi man, absolutely amazing tutorial, my dev team managed to get it up an running in no time.
However, we are facing two problems, one is related to babel plugins, no matter what i did, i could not add the @babel/plugin-transform-react-jsx, therefore the web package crashes:

../commons/pages/tabs/tabs.page.js
SyntaxError: /home/praetors/Projects/node/proyectoSembrar/packages/commons/pages/tabs/tabs.page.js: Support for the experimental syntax 'jsx' isn't currently enabled (16:9):

  14 | const dummyTab = () => {
  15 |     return (
> 16 |         <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
     |         ^
  17 |             <Text>Test</Text>
  18 |         </View>
  19 |     );

Add @babel/plugin-transform-react-jsx (https://git.io/vb4yd) to the 'plugins' section of your Babel config to enable transformation.

The other problem comes with react-native-vector-icons: ^7.0.0, we added the:

apply from: "../../../../node_modules/react-native-vector-icons/fonts.gradle"

but we could not get them to render in android, instead it shows the crossed box, here is how we implemented it:

import Icon from 'react-native-vector-icons/Ionicons';

export default function Tabs() {
    return (
        <Tab.Navigator
           //...
            screenOptions={({ route }) => ({
                tabBarIcon: ({
                    focused, color, size
                }) => {
                    let iconName;
                    switch (route.name) {
                        case 'Inicio':
                            iconName = focused ? 'ios-home' : 'ios-home-outline';
                            break;
                    //...
                    }
                    return <Icon name={iconName} size={size} color={color} />;
                }
            })}>
            <Tab.Screen name="Inicio" component={Home} />
             //...
        </Tab.Navigator>
    )
}

Andrei Melo • Oct 30 '20

try this, please see the following :
step

npm install @babel/plugin-transform-react-jsx or yarn add @babel/plugin-transform-react-jsx
go to config-overrides.js : Then add the package installed to plugins...
please see below,

const fs = require('fs');
const path = require('path');
const webpack = require('webpack');

const appDirectory = fs.realpathSync(process.cwd());
const resolveApp = (relativePath) => path.resolve(appDirectory, relativePath);

// our packages that will now be included in the CRA build step
const appIncludes = [
resolveApp('src'),
resolveApp('../common/src'),
resolveApp('../../node_modules/@react-navigation'),
resolveApp('../../node_modules/react-navigation'),
resolveApp('../../node_modules/react-native-gesture-handler'),
resolveApp('../../node_modules/react-native-screens'),
];

module.exports = function override(config, env){
config.module.rules.push({
test : /.(js|mjs|tsx|ts)$/,
exclude : /@babel(?:\/|\{1,2})runtime/,
use : {
loader : 'babel-loader',
options : {
babelrc : false,
configFile : false,
compact : false,
// The configration for compilation
presets : [
[
'module:metro-react-native-babel-preset',
], // Add this line,
[
require.resolve('babel-preset-react-app/dependencies'),
{ helpers: true },
],
],
cacheDirectory : true,
plugins : [
'@babel/plugin-proposal-class-properties',
'@babel/plugin-proposal-object-rest-spread',
'@babel/plugin-transform-flow-strip-types',
'@babel/plugin-transform-react-jsx'
[
'module-resolver',
{
alias : {
'^react-native$' : 'react-native-web',
},
},
],
],
},
},
});
return config;
};

thanks

Andrei Melo • Oct 30 '20

paste it to *config-overrides.js

Nitesh Agarwal • Mar 9 '22

This JS is not valid (check module-resolver)

Varun Gupta • Dec 9 '20

I am able to run this setup in Dev mode on both ios and android but when I create a releaze, I get an error saying the shared package is not found because it is a symlink and metro bundler doesn't support symlink yet. Were you able to create release builds? If yes, were there any changes required?

Bruno Lemos • Dec 9 '20

ios or android? which react-native version? what's your operating system? try using the latest react-native version and maybe also try using the yarn resolutions feature to force it use the latest version of @react-native-community/cli which as of today is 5.0.1-alpha.0.

Varun Gupta • Dec 10 '20

So, I have a mobile app in production on iOS and Android that we plan to provide over the browser also. To reuse the logic code in the web app, I am putting those in shared packages managed using the yarn workspaces. Initially, I was using react-native 0.63.3 which uses react 16.13.1 for the mobile app. When I created the web app, it was using react 17.0.1. There were a couple of invalid hook call errors which happen due to conflicting versions of react. I tried no-hoisting react and react-native specific packages but that resulted in some packages under root node modules and some under the package node_modules which becomes problematic during auto-linking. So, I ended up upgrading react-native to 0.64.0-rc.1 which uses react 17.0.1. I was able to build and run the app on both iOS and Android but when I created the release build, I got some errors mainly around not able to find the shared packages since they are symlinks and metro doesn't support symlinks. I read about some workaround by providing extraNodeModules and projectRoots in metro.config.js but I kept on getting one error or the other.

I wanted to ask if you made any special changes to create release builds for your app and what are those?

After banging my head for the last few days to convert the existing app to the mono-repo, I started out creating a brand new app in a mono-repo structure, have a dummy shared package and create release builds from it and then port my code over. I am getting the below error on iOS while creating an archive. I am able to run the app in dev mode:

error: Build input file cannot be found: '/Users/varungupta/Projects/galarm-combined/node_modules/react-native/Libraries/FBReactNativeSpec/FBReactNativeSpec/FBReactNativeSpec-generated.mm' (in target 'FBReactNativeSpec' from project 'Pods')

This error doesn't appear if I create a new project and create an archive without making it into a mono-repo.

One more thing I wanted to ask is do I need to change the paths in node_modules/react-native/scripts/react_native_pods.rb and react.gradle files as they contain some references to node_modules.

Bruno Lemos • Dec 11 '20 • Edited

Do not use nohoist, this causes many problems like the issue with metro you mentioned
Make sure you use the exact same version of the dependencies between the projects (e.g. react "17.0.1", without "^" or "~")
Make sure that all your "node_modules" are empty inside the packages. The only one with dependencies should be the node_modules in the root folder. If they are not empty, you probably have dependencies with different versions. You can use yarn resolutions to fix that.
Set projectRoot in the metro config and change the entry files to packages/mobile/index as mentioned in the article
RN 0.64 is still in beta and has issues. Of the of the issues is this one about FBReactNativeSpec, you need to run "pod install" again every time after you run "yarn".
Yes you need to change all references of node_modules/react-native. Including on podfile and creating a react-native.config.js file

See this repository: github.com/brunolemos/react-native...

Varun Gupta • Dec 12 '20

Dear Bruno,

Thanks for your response. I am already doing #2 as yarn seem to update the packages without updating package.json if there are minor upgrades available. I was not aware of the yarn resolutions but that is pretty cool I do have some node_modules in my web and mobile folder which I will fix using yarn resolutions.

For setting the project root in metro.config.js, I guess I just need to set it to the dirname like projectRoot: path.resolve(dirname, '.')

For the react-native.config.js file, could you please tell me where and how it is used. I created it based on your blog instructions but I am not sure how it is used.

Also, I checked the devhub repository (great resource btw), it doesn't have a react-native.config.js file or setting a projectRoot in metro.config.js file.

Thanks again for your valuable time.

View full discussion (158 comments)

DEV Community

Tutorial: How to share code between iOS, Android & Web using React Native, react-native-web and monorepo

Why am I writing this?

What's `react-native-web`?

Summary

Step-by-step tutorial

Starting a new `React Native` project

Turning our folder structure into a monorepo

Making react-native work in a monorepo

iOS changes

Android changes

Sharing code between our monorepo packages

Web project

Creating a new web project using CRA and react-native-web

Making CRA work inside our monorepo with code sharing

Some gotchas

Some tips

Links

Top comments (158)

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Why am I writing this?

What's react-native-web?

Summary

Step-by-step tutorial

Starting a new React Native project

Turning our folder structure into a monorepo

Making react-native work in a monorepo

iOS changes

Android changes

Sharing code between our monorepo packages

Web project

Creating a new web project using CRA and react-native-web

Making CRA work inside our monorepo with code sharing

Some gotchas

Some tips

Links

Read next

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