devNix.j2

{% set perPackageManager = {
    "npm": {
        "packages": "pkgs.nodejs_20",
        "install": "npm ci --prefer-offline --no-audit --no-progress --timing && npm i @expo/ngrok@^4.1.0 react@latest react-dom@latest react-native@latest && npm i -D @types/react@latest",
        "previewWebPrefix": "\"npm\" \"run\" \"web\" \"--\"",
        "previewAndroidPrefix": "npm run android --",
        "installDevClient": "npx -y expo install expo-dev-client"
    },
    "bun": {
        "packages": "pkgs.bun",
        "install": "bun i @expo/ngrok@^4.1.0 react@latest react-dom@latest react-native@latest && bun i -D @types/react@latest",
        "previewWebPrefix": "\"bun\" \"web\"",
        "previewAndroidPrefix": "bun android",
        "installDevClient": "bunx expo install expo-dev-client"
    },
    "pnpm": {
        "packages": "pkgs.nodePackages.pnpm",
        "install": "pnpm add @expo/ngrok@^4.1.0 react@latest react-dom@latest react-native@latest && pnpm i -D @types/react@latest",
        "previewWebPrefix": "\"pnpm\" \"web\"",
        "previewAndroidPrefix": "pnpm android",
        "installDevClient": "pnpx expo install expo-dev-client"
    },
    "yarn": {
        "packages": "pkgs.yarn",
        "install": "yarn && yarn add @expo/ngrok@^4.1.0 react@latest react-dom@latest react-native@latest && yard add -D @types/react@latest",
        "previewWebPrefix": "\"yarn\" \"web\"",
        "previewAndroidPrefix": "yarn android",
        "installDevClient": "yarn dlx expo install expo-dev-client"
    },
}[packageManager]%}# To learn more about how to use Nix to configure your environment
# see: https://developers.google.com/idx/guides/customize-idx-env
{ pkgs, ... }: {
  # Which nixpkgs channel to use.
  channel = "stable-25.05";
  # Use https://search.nixos.org/packages to find packages
  packages = {% if openIn == "development" %}[{{perPackageManager.packages}} pkgs.nodejs_20 pkgs.jdk21_headless pkgs.gradle]{% else %}[{{perPackageManager.packages}}]{% endif %};
  # Sets environment variables in the workspace
  env = {
    EXPO_USE_FAST_RESOLVER = 1; 
  };
  idx = {
    # Search for the extensions you want on https://open-vsx.org/ and use "publisher.id"
    extensions = [
      "msjsdiag.vscode-react-native"
      {% if openIn == "development" %}
      "fwcd.kotlin"
      {% endif %}
    ];
    workspace = {
      # Runs when a workspace is first created with this `dev.nix` file
      onCreate = {
        {% if openIn == "development" %}
        install-and-prebuild = ''
          {{perPackageManager.install}} && {{perPackageManager.installDevClient}} && npx -y expo prebuild --platform android
          # Add more memory to the JVM
          sed -i 's/org.gradle.jvmargs=-Xmx2048m -XX:MaxMetaspaceSize=512m/org.gradle.jvmargs=-Xmx4g -XX:MaxMetaspaceSize=512m/' "android/gradle.properties"
        '';
        {% else %}
        install = "{{perPackageManager.install}}";
        {% endif %}
      };
      # Runs when a workspace restarted
      onStart = {
         android = ''
          echo -e "\033[1;33mWaiting for Android emulator to be ready...\033[0m"
          # Wait for the device connection command to finish
          adb -s emulator-5554 wait-for-device && \
          {% if openIn == "development" %}
          {{packageManager}} run android
          {% else %}
          {{perPackageManager.previewAndroidPrefix}} --tunnel
          {% endif %}
        '';
      };
    };
    # Enable previews and customize configuration
    previews = {
      enable = true;
      previews = {
        web = {
          command = [{{perPackageManager.previewWebPrefix}} "--port" "$PORT"];
          manager = "web";
        };
        android = {
          # noop
          command = ["tail" "-f" "/dev/null"];
          manager = "web";
        };
      };
    };
  };
}