Using rig packages

In a large scale environment, it's common for many projects to be built using the exact same Heft configuration. There may be some differences -- for example, a Node.js project may emit CommonJS modules, whereas a web application project may need to emit ESNext modules. But generally a small handful of common "profiles" will cover most projects. We can avoid this duplication by moving common settings into an NPM package which gets added to the "devDependencies" for the projects that consume it. This is called a rig package. Note that several different rig profiles may come from the same NPM package; each profile is a folder containing a set of config files.

Heft also provides two standard rig packages that you can use in your projects:

• @rushstack/heft-node-rig with a profile called default
• @rushstack/heft-web-rig with a profile called library

It's also easy to define your own custom rig packages.

The heft-node-rig-tutorial sample project illustrates how to consume @rushstack/heft-node-rig.

Let's look at three different ways that rig packages influence the build.

1. Base files for "extends"

Many config files provide a facility for inheriting shared settings from another file. For example, in our sample project, the TypeScript configuration is reduced to just a few lines:

heft-node-rig-tutorial/tsconfig.json

{
  "extends": "./node_modules/@rushstack/heft-node-rig/profiles/default/tsconfig-base.json",
  "compilerOptions": {
    "types": ["heft-jest", "node"]
  }
}

The bulk of the settings come from tsconfig-base.json in the default profile. But our local tsconfig.json file can add custom settings such as "types" as needed.

The following config files all support a field such as "extends" that enables settings to be inherited from another NPM package:

• .eslintrc.js for the eslint task, provided that you use the @rushstack/eslint-patch workaround or the @rushstack/eslint-config ruleset (which includes the patch)
• config/api-extractor.json for the api-extractor task
• config/jest.config.json for the jest task
• tsconfig.json for the typescript task
• tslint.json for the tslint task
• webpack.config.js does not explicitly support inheritance, but being a JavaScript module, it can call require() to load shared settings.

2. "Riggable" config files

In the above example, we cannot eliminate tsconfig.json entirely because tools such as VS Code expect to find this file in the root of your project folder. This is true of a few other files such as .eslintrc.js. Aside from these special cases, most other Heft config files can be eliminated entirely by creating a rig.json file, as seen in the heft-node-rig-tutorial project:

heft-node-rig-tutorial/config/rig.json

// The "rig.json" file directs tools to look for their config files in an external package.
// Documentation for this system: https://www.npmjs.com/package/@rushstack/rig-package
{
  "$schema": "https://developer.microsoft.com/json-schemas/rig-package/rig.schema.json",

  /**
   * (Required) The name of the rig package to inherit from.
   * It should be an NPM package name with the "-rig" suffix.
   */
  "rigPackageName": "@rushstack/heft-node-rig"

  /**
   * (Optional) Selects a config profile from the rig package.  The name must consist of
   * lowercase alphanumeric words separated by hyphens, for example "sample-profile".
   * If omitted, then the "default" profile will be used."
   */
  // "rigProfile": "your-profile-name"
}

The rig.json file tells Heft that if it doesn't find a file in the heft-node-rig-tutorial/config, it should try looking in the @rushstack/heft-node-rig/profiles/default/common folder instead.

Examples of "riggable" config files:

• <project folder>/config/api-extractor-task.json
• <project folder>/config/heft.json
• <project folder>/config/typescript.json

3. Riggable dependencies

The rig package can also provide NPM dependencies, to avoid having to specify them as "devDependencies" for your project. The following tool packages can be provided by the rig:

• typescript
• @microsoft/api-extractor
• eslint
• tslint

Today, only these packages can be provided via a rig. Providing dependencies via a rig is optional. Your local project's devDependencies take precedence over the rig.

Heft resolves each riggable tool independently, using the following procedure:

1. If the tool package is listed in the devDependencies for the local project, then the tool is resolved from the current project folder. (This step does NOT consider dependencies or peerDependencies.)

2. OTHERWISE, if the current project has a rig.json file, and if the rig's package.json lists the tool in its dependencies, then the tool is resolved from the rig package folder. (This step does NOT consider devDependencies or peerDependencies.)

3. OTHERWISE, the tool is resolved from the current project folder. If it can't be found there, then an error is reported.

Note: Prior to version 0.25.0, Heft used a different lookup strategy that did not rely on rig.json. It worked like this: While parsing the tsconfig.json file for a project, if the "extends" field referred to a file from an NPM package, Heft would look to see if that package had a direct dependency on the typescript package. If so, ALL riggable tools would be resolved from that folder.

Heft itself has a direct dependency on the following packages, so your project does not need to depend on them:

• webpack and webpack-dev-server
• jest and its core dependencies

See also

• @rushstack/rig-package documentation provides the complete specification for the rig.json system
• heft-node-rig-tutorial sample project