Stop Heroku from Pruning Dev Dependencies

Question

I have been trying to stop heroku from pruning my dev dependencies. Here is my config: My build script is: "build": "NPM_CONFIG_PRODUCTION=false webpack -mode production" And I have added "heroku-postbuild": "npm run build" My Dependencies:

"dependencies": {
    "express": "^4.16.3",
    "react": "^16.5.2",
    "react-dom": "^16.5.2"
  },
  "devDependencies": {
    "@babel/core": "^7.0.0",
    "@babel/plugin-proposal-class-properties": "^7.0.0",
    "@babel/preset-env": "^7.0.0",
    "@babel/preset-react": "^7.0.0",
    "babel-eslint": "^10.0.0",
    "babel-loader": "^8.0.0",
    "clean-webpack-plugin": "^0.1.19",
    "concurrently": "^4.0.0",
    "css-loader": "^1.0.0",
    "eslint": "^5.0.0",
    "eslint-config-airbnb": "^17.0.0",
    "eslint-plugin-import": "^2.11.0",
    "eslint-plugin-jsx-a11y": "^6.0.3",
    "eslint-plugin-react": "^7.7.0",
    "file-loader": "^2.0.0",
    "html-webpack-plugin": "^3.2.0",
    "nodemon": "^1.17.3",
    "style-loader": "^0.23.0",
    "url-loader": "^1.0.1",
    "webpack": "^4.5.0",
    "webpack-cli": "^3.0.8",
    "webpack-dev-server": "^3.1.3"
  }

I would appreciate any help with the config as I don't want to add my dev dependencies to my dependencies.

Answer 1

Set Heroku env var NPM_CONFIG_PRODUCTION to false with

heroku config:set NPM_CONFIG_PRODUCTION=false

instead of trying to set it in your npm script. See docs.