yarn-error

gistfile1.txt

{
  "dependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-stage-0": "^6.24.1",
    "body-parser": "^1.19.0",
    "concurrently": "^4.1.0",
    "express": "^4.17.1",
    "mongoose": "^5.5.14",
    "morgan": "^1.9.1",
    "nodemon": "^1.19.1"
  }
  "scripts": {
    "start:server": "cd backend && nodemon server.js --exec babel-node --presets es2015,stage-0",
    "start:client": "cd client && yarn start",
    "start:dev": "concurrently \"yarn start:server\" \"yarn start:client\""
  }
}

// In main package.json (outside client/ and backend/ folder, add the start:server, start:client, and start:dev as shown below

// "test": //... unchanged
// "start:server": "cd backend && nodemon server.js --exec babel-node --presets es2015,stage-0",
// "start:client": "cd client && yarn start",
// "start:dev": "concurrently \"yarn start:server\" \"yarn start:client\""