tsdx - react is null, prevents hook usage

Question

I've recently tried creating a react typescript component using tsdx to compile and I've hit a bit of a wall when debugging. The package is published and seemingly being published and installed without error. However, when it comes to actually being used I'm always met with:

TypeError: Cannot read properties of null (reading 'useEffect').

I had the same issue with useContext so simply replaced the functionality but now the error has migrated to useEffect.

This package runs totally fine locally, if I rip out all the code and inject it into an app manually it runs without issue. Initially I was just destructuring the useEffect hook from react but even when explicitly importing react as import React from 'react'; react is still apparently null...

Looking into the .cjs files I can see React being imported:

var React = _interopDefault(require('react'));

yet the issue persists.

Any and all help is appreciated, will paste some info from my package.json if it helps :)

{
  "name": "xxxx",
  "version": "x.x.x",
  "description": "xxxx",
  "author": "xxx xxx",
  "keywords": [],
  "main": "dist/index.js",
  "module": "dist/xxx.esm.js",
  "typings": "dist/index.d.ts",
  "engines": {
    "node": ">=10"
  },
  "files": [
    "dist",
    "src",
    "README.md"
  ],
  "repository": {
    "type": "git",
    "url": "git+https://github.com/xxxx/xxxx.git"
  },
  "dependencies": {
    "@babel/polyfill": "^7.12.1",
    "@testing-library/jest-dom": "^5.16.4",
    "@testing-library/react": "^13.2.0",
    "@testing-library/user-event": "^13.5.0",
    "@types/jest": "^27.5.0",
    "@types/node": "^16.11.34",
    "@types/react": "^18.0.9",
    "@types/react-dom": "^18.0.3",
    "axios": "^0.27.2",
    "react": "^18.1.0",
    "react-dom": "^18.1.0",
    "react-scripts": "5.0.1",
    "typescript": "^4.6.4",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "npx tsdx build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "@babel/cli": "^7.17.10",
    "@babel/core": "^7.17.12",
    "@babel/preset-env": "^7.17.12"
  },
  "bugs": {
    "url": "https://github.com/xxxx/xxxx/issues"
  },
  "homepage": "https://github.com/xxxx/xxxx#readme",
  "license": "ISC"
}

Edit: Also if it's worth noting - this project was not initialised as a tsdx project, I added the tsdx build script and some elements to the tsconfig and package.json after running into packaging issues prior to switching

Answer 1

Just leaving a note for anyone else that encounters this, in my package I had "react" and a number of other dependencies in a regular dependencies object in my package.json, the issue seemed to resolve when I moved these to devDependencies.