#Adopting Rune in a monorepo

Adoption is per script and per package. A repository can run one script through Rune and leave the rest alone for as long as it likes.

#Seeding the config from an existing package

rune init --from-package-json reads the nearest package.json and writes one command script per entry in its scripts field. Start from the package whose scripts are the most copied.

From inside packages/api:

npx rune init --from-package-json

yarn rune init --from-package-json

pnpm rune init --from-package-json

bun rune init --from-package-json

Move the generated file to the repository root, then delete the entries that are genuinely local to one package. What remains is the shared set.

#Switching packages over

For each package, replace the command string with a reference:

  "scripts": {
-   "test": "vitest run --coverage --reporter=dot --pool=threads",
+   "test": "rune run test"
  }

Run rune list from inside the package to confirm the name resolves before deleting the original string.

#The package that needs one extra flag

This is the case that usually stops a shared script from being shared. Put a rune.config.ts in that package and extend the root definition.

import { defineConfig } from '@giancarlosio/rune';

export default defineConfig({
  scripts: {
    test: {
      extends: 'test',
      appendArgs: ['--maxWorkers=1'],
    },
  },
});

rune run test inside packages/legacy now runs the root command with the extra flag. Every other package is unchanged, and packages/legacy/package.json still says rune run test.

An override may extend a script. It may not replace one. A package config that defines test with its own command is a validation error, because a name that means two different things across the repository is the duplication Rune removes. If the command really is different, give it a different name.

#Checking what a package resolves to

From inside packages/legacy:

npx rune inspect test

yarn rune inspect test

pnpm rune inspect test

bun rune inspect test

inspect prints the resolved command, the working directory, the environment delta and the chain of definitions that produced them. It never spawns anything.

#Verifying the whole repository

npm exec --workspaces -- rune list

yarn workspaces foreach -A exec rune list

pnpm -r exec rune list

bun run --filter "*" rune list

Each package prints the scripts visible to it, with (overridden here) next to the ones its own config sharpens.

#Next

Turborepo and Nx covers the one configuration change a task runner needs once script strings stop changing.