neutrino-dev/docs/customization/simple.md

Simple Neutrino Customization

No two JavaScript projects are ever the same, and as such there may be times when you will need to make modifications to the way your Neutrino preset is building your project. By defining a configuration object within your package.json, Neutrino will merge this information with that provided by your preset, effectively overriding those options with your custom data.

Prepare package.json

First, you will need to define a config section within your package.json. You may have already done this if you specified your presets through the config as opposed to flags through scripts:

{
  "config": {
    "presets": [
      "neutrino-preset-react",
      "neutrino-preset-karma"
    ]
  },
  "scripts": {
    "start": "neutrino start",
    "build": "neutrino build"
  }
}

Add a new property to config named neutrino. This will be an object where we can provide configuration data:

{
  "config": {
    "presets": [],
    "neutrino": {

    }
  }
}

Populate this object with configuration overrides. This is not a Webpack configuration, but rather a Neutrino-compatible object based on webpack-chain.

Usage

Entries

Add files to named entry points, or define new entry points. This is a key named entry, with a value being an object. This maps to points to enter the application. At this point the application starts executing.

Example: Define an entry point named vendor that bundles React packages separately from the application code.

{
  "config": {
    "neutrino": {
      "entry": {
        "vendor": [
          "react",
          "react-dom",
          "react-hot-loader",
          "react-router-dom"
        ]
      }
    }
  }
}

Module

The module object defines how the different types of modules within a project will be treated. Any additional properties attached to module not defined below will be set on the final module configuration.

Module Rules

Using module.rule creates rules that are matched to requests when modules are created. These rules can modify how the module is created. They can apply loaders to the module, or modify the parser.

Using module.rule.loader allows to you define the Webpack loader and its options for processing a particular rule. This loader is usually a dependency or devDependency of your project. Each loader object can specify a property for the string loader and an options object.

Example: Add LESS loading to the project.

{
  "dependencies": {
    "less": "^2.7.2",
    "less-loader": "^2.2.3"
  },
  "config": {
    "neutrino": {
      "module": {
        "rule": {
          "styles": {
            "test": "\\.less$",
            "loader": {
              "less": {
                "loader": "less-loader",
                "options": {
                  "noIeCompat": true
                }
              }
            }
          }
        }
      }
    }
  }
}

Output

The output object contains a set of options instructing Webpack on how and where it should output your bundles, assets, and anything else you bundle or load with Webpack. This option can be any property/value combination that Webpack accepts.

Example: Change the public path of the application.

{
  "config": {
    "neutrino": {
      "output": {
        "publicPath": "https://cdn.example.com/assets/"
      }
    }
  }
}

Node

Use node to customize the Node.js environment using polyfills or mocks:

Example: mock the __filename and __dirname Node.js globals.

{
  "config": {
    "neutrino": {
      "node": {
        "__filename": "mock",
        "__dirname": "mock"
      }
    }
  }
}

DevServer

Use devServer to customize webpack-dev-server and change its behavior in various ways.

Example: gzip the application when serving and listen on port 9000.

{
  "config": {
    "neutrino": {
      "devServer": {
        "compress": true,
        "port": 9000
      }
    }
  }
}

Resolve

Use resolve to change how modules are resolved. When using resolve.extensions and resolve.modules, these should be specified as arrays, and will be merged with their respective definitions used in inherited presets. Any additional properties attached to resolve not defined below will be set on the final module configuration.

Example: Add .mjs as a resolving extension and specify modules are located in a custom_modules directory.

{
  "config": {
    "neutrino": {
      "resolve": {
        "extensions": [".mjs"],
        "modules": ["custom_modules"]
      }
    }
  }
}

ResolveLoader

Use resolveLoader to change how loader packages are resolved. When using resolveLoader.extensions and resolveLoader.modules, these should be specified as arrays, and will be merged with their respective definitions used in inherited presets. Any additional properties attached to resolveLoader not defined below will be set on the final module configuration.

Example: Add .loader.js as a loader extension and specify modules are located in a web_loaders directory.

{
  "config": {
    "neutrino": {
      "resolve": {
        "extensions": [".loader.js"],
        "modules": ["web_loaders"]
      }
    }
  }
}

Additional configuration

Any top-level properties you set on config.neutrino will be added to the configuration.

Example: Change the Webpack performance options to error when exceeding performance budgets.

{
  "config": {
    "neutrino": {
      "performance": {
        "hints": "error"
      }
    }
  }
}

Advanced Configuration

With the options defined above in your package.json, you can perform a variety of build customizations on a per-project basis. In the event that you need more customization than what is afforded through JSON, consider either switching to advanced configuration, or creating your own preset.