monorepo: expo with yarn workspace and using expo install

Question

I'm trying to setup a React and Expo monorepo project, everything seems good until I want to install react-navigation with expo install according to the react-navigation docs, because expo install use yarn in the background and because it's a workspace environment this error pop out, which I have no idea how to bypass. any ideas?

yarn add v1.21.1
info Visit https://yarnpkg.com/en/docs/cli/add for documentation about this command.
error Running this command will add the dependency to the workspace root rather than the workspace itself, which might not be what you 
want - if you really meant it, make it explicit by running this command again with the -W flag (or --ignore-workspace-root-check).     
yarnpkg exited with non-zero code: 1
Set EXPO_DEBUG=true in your env to view the stack trace.

Answer 1

This is how i got it to work with expo-yarn-workspaces.
In my global package.json file i added the following codes.

{
  "private": true,
  "workspaces": [
    "packages/*"
  ],
}

then i created a folder in my root directory called packages.
In my terminal i cd packages then i created a new expo project with this command

expo init app

Define the name and version properties in package.json.

then i installed all my dependencies:

npm install

or

yarn

now its time to install expo-yarn-workspaces with

npm install --save-dev expo-yarn-workspaces

or

yarn add expo-yarn-workspaces -D

After that you add this script in your package.json

"scripts": {
    ...,
    "postinstall": "expo-yarn-workspaces postinstall"
  },

create a file and name it metro.config.js and paste the following code

const { createMetroConfiguration } = require("expo-yarn-workspaces");

module.exports = createMetroConfiguration(__dirname);

in your package.json replace/add this line of code

"main": "__generated__/AppEntry.js",

Run:

npm run postinstall

or

yarn postinstall

then you can start your app with the following command to clear the cache:

npm start --clear

or

yarn start --clear

NOTE: If you're running create-react-app and react-native they most be of the same version so you have to run npm install react react-dom in both folders to be able to use the same version.

---

My github repo

Useful links:

Article https://divinehycenth.com/blog/yarn-workspace-monorepo.

Github https://github.com/expo/expo/tree/master/packages/expo-yarn-workspaces

Hope it solves your problem.