React-native, monorepo: Unable to resolve module @babel/runtime/helpers/interopRequireDefault

I've set up a react-native app as workspace in a monorepo. I did this because I want to share some react components I've created between my mobile and web apps.

The basic structure of my repo is:

root/
    package.json (with nohoist: ["**/expoapp/**"])
    modules/
        ...shared modules, some simple JS, some react
    apps/
        web/  (cra-based web app)
        mobile/
            package.json
            metro.config.js (addes watchFolders and extraNodeModules)
            App.js

I am able to import simple JS modules into my mobile app from the modules directory.

But when I try to import one of my react components, I get this error:

Unable to resolve module @babel/runtime/helpers/interopRequireDefault from /Users/jim/development/.../modules/dumb-module/index.js: @babel/runtime/helpers/interopRequireDefault could not be found within the project.

The error message in the console points to the first line of my react component:

iOS Bundling failed 3378ms
Unable to resolve module @babel/runtime/helpers/interopRequireDefault from /Users/jim/development/.../modules/dumb-module/index.js: @babel/runtime/helpers/interopRequireDefault could not be found within the project.

If you are sure the module exists, try these steps:
 1. Clear watchman watches: watchman watch-del-all
 2. Delete node_modules and run yarn install
 3. Reset Metro's cache: yarn start --reset-cache
 4. Remove the cache: rm -rf /tmp/metro-*
> 1 | import React from 'react';
  2 |
  3 | const DumbModule = () => {
  4 |     return (

DumbModule is an intentionally simple react component:

import React from 'react';

const DumbModule = () => {
    return (
        <div>I am useless.</div>
    );
};

export default DumbModule;

I add it to App.js like so:

import DumbModule from '@mymodules/dumb-module';

The dependencies in my react-native app are:

  "devDependencies": {
    "@babel/runtime": "^7.15.4",
    "@react-navigation/native": "^6.0.2",
    "@react-navigation/native-stack": "^6.2.0",
    "react": "17.0.2",
    "react-native": "0.65.1",
    "react-native-safe-area-context": "^3.3.2",
    "react-native-screens": "^3.7.2",
    "@babel/core": "^7.12.9",
    "@react-native-community/eslint-config": "^2.0.0",
    "babel-jest": "^26.6.3",
    "eslint": "7.14.0",
    "jest": "^26.6.3",
    "metro-react-native-babel-preset": "^0.66.0",
    "react-native-codegen": "^0.0.7",
    "react-test-renderer": "17.0.2"
  },

If I disable the import into App.js, the app runs fine. If I enable it, I get the above message pointing at the first line of my component.

I've been through every suggestion I can find. No luck.

Any ideas?

Solution

We were able to work around this problem by adding the path to the project's node_modules directory to the nodeModulesPaths array in metro.config.js. It would appear that when metro is resolving the dependencies of the external module (dumb-module) it didn't automatically know to look in the project's own node_modules, so it couldn't find react.

Of course, it would have been helpful if the error message didn't refer to an unrelated babel file.

Here's my updated metro.config.js:

const path = require('path');

const extraNodeModules = {
    'modules': path.resolve(path.join(__dirname, '../../modules'))
};

const watchFolders = [
    path.resolve(path.join(__dirname, '../../modules'))
];

const nodeModulesPaths = [path.resolve(path.join(__dirname, './node_modules'))];

module.exports = {
    transformer: {
        getTransformOptions: async () => ({
            transform: {
                experimentalImportSupport: true,
                inlineRequires: true,
            },
        }),
    },
    resolver: {
        extraNodeModules,
        nodeModulesPaths
    },
    watchFolders
};