working bsconfig and package.json for https://dev.to/iwilsonq/reasonml-with-react-hooks-tutorial-building-a-pomodoro-timer-57h0

bsconfig.json

{
  "name": "react-template",
  "reason": {
    "react-jsx": 3
  },
  "sources": {
    "dir" : "src",
    "subdirs" : true
  },
  "package-specs": [{
    "module": "commonjs",
    "in-source": false
  }],
  "suffix": ".bs.js",
  "namespace": true,
  "bs-dependencies": [
    "reason-react"
  ],
  "refmt": 3
}

package.json

{
  "name": "pomodoro-timer",
  "version": "0.1.0",
  "scripts": {
    "build": "bsb -make-world",
    "start": "bsb -make-world -w",
    "clean": "bsb -clean-world",
    "test": "echo \"Error: no test specified\" && exit 1",
    "webpack": "webpack -w",
    "webpack:production": "NODE_ENV=production webpack",
    "server": "webpack-dev-server"
  },
  "keywords": [
    "BuckleScript"
  ],
  "author": "",
  "license": "MIT",
  "dependencies": {
    "react": "^16.8.6",
    "react-dom": "^16.8.6",
    "reason-react": ">=0.7.0"
  },
  "devDependencies": {
    "bs-platform": "^5.0.2",
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.0.1",
    "webpack-cli": "^3.1.1",
    "webpack-dev-server": "^3.1.8"
  }
}