Node Package API

Shakapacker ships a Node package that exposes configuration and helper utilities for both webpack and rspack.

Import Paths

// Webpack entrypoint
const shakapacker = require("shakapacker")

// Rspack entrypoint
const rspack = require("shakapacker/rspack")

Webpack Exports (shakapacker)

Export	Type	Description
config	object	Parsed config/shakapacker.yml plus computed fields
devServer	object	Dev server configuration
generateWebpackConfig(extraConfig?)	function	Generates final webpack config and merges optional overrides
baseConfig	object	Base config object from package/environments/base
env	object	Environment metadata (railsEnv, nodeEnv, booleans)
rules	array	Loader rules for current bundler
moduleExists(name)	function	Returns whether module can be resolved
canProcess(rule, fn)	function	Runs callback only if loader dependency is available
inliningCss	boolean	Whether CSS should be inlined in current dev-server mode
merge, mergeWithCustomize, mergeWithRules, unique	functions	Re-exported from webpack-merge

Rspack Exports (shakapacker/rspack)

Export	Type	Description
config	object	Parsed config/shakapacker.yml plus computed fields
devServer	object	Dev server configuration
generateRspackConfig(extraConfig?)	function	Generates final rspack config and merges optional overrides
baseConfig	object	Base config object
env	object	Environment metadata (railsEnv, nodeEnv, booleans)
rules	array	Rspack loader rules
moduleExists(name)	function	Returns whether module can be resolved
canProcess(rule, fn)	function	Runs callback only if loader dependency is available
inliningCss	boolean	Whether CSS should be inlined in current dev-server mode
merge, mergeWithCustomize, mergeWithRules, unique	functions	Re-exported from webpack-merge

config Object

config includes:

• Raw values from config/shakapacker.yml (source_path, public_output_path, javascript_transpiler, etc.)
• Computed absolute paths (outputPath, publicPath, manifestPath, publicPathWithoutCDN)
• Optional sections like dev_server and integrity

For the full key list and types, see:

• package/types.ts
• Configuration Guide

Built-in Third-Party Support

Installer defaults include support for:

• Bundlers: webpack, rspack
• JavaScript transpilers: SWC (default), Babel, esbuild
• Common style/tooling loaders: css, sass, less, stylus, file/raw rules
• Common optimization/plugins for webpack/rspack production builds

Dependency presets used by the installer are defined in:

• lib/install/package.json