monorepo-task-runner

Enforce that all packages use a centralized task runner instead of package.json scripts.

Rule details

In a monorepo, package.json scripts are local to each package and cannot express cross-package dependencies, caching, or orchestration. This rule enforces that all packages use a centralized task runner (e.g., Moon, Turborepo, Nx) by banning scripts in package.json and requiring a task runner config file (moon.yml, turbo.json, etc.) in every package.

Examples of incorrect code

packages/api/package.json

{
  "name": "@myorg/api",
  "scripts": { "build": "tsc", "test": "vitest", "lint": "eslint ." }
}

Examples of correct code

packages/api/package.json

{ "name": "@myorg/api" }

packages/api/moon.yml

tasks:
  build:
    command: tsc
    inputs:
      - src/**/*
  test:
    command: vitest
    deps:
      - ~:build
  lint:
    command: eslint .

Rule implementation

/// <reference path="../rules.d.ts" />

export default {
  rules: {
    "no-package-scripts": {
      description:
        "package.json must not have scripts — use the task runner instead",
      async check(ctx) {
        const packageJsonFiles = [
          ...(await ctx.glob("packages/*/package.json")),
          ...(await ctx.glob("packages/*/*/package.json")),
        ];

        for (const file of packageJsonFiles) {
          const pkg = (await ctx.readJSON(file)) as {
            scripts?: Record<string, string>;
          };
          if (pkg.scripts && Object.keys(pkg.scripts).length > 0) {
            ctx.report.violation({
              message: `${file}: has "scripts" field — use task runner config instead`,
              file,
              fix: 'Move scripts to the task runner config and remove "scripts" from package.json',
            });
          }
        }
      },
    },
    "task-runner-config": {
      description: "All packages must have a task runner configuration file",
      async check(ctx) {
        const packageJsonFiles = [
          ...(await ctx.glob("packages/*/package.json")),
          ...(await ctx.glob("packages/*/*/package.json")),
        ];

        for (const file of packageJsonFiles) {
          const configPath = file.replace("/package.json", "/moon.yml");
          try {
            await ctx.readFile(configPath);
          } catch {
            ctx.report.violation({
              message: `Missing task runner config: ${configPath}`,
              file: configPath,
              fix: "Create a moon.yml file with appropriate task definitions for this package",
            });
          }
        }
      },
    },
  },
} satisfies RuleSet;

When to use it

In monorepos that use a centralized task runner for build orchestration. Adapt the config file check for your runner:

// Turborepo
const configPath = file.replace("/package.json", "/turbo.json");

// Nx
const configPath = file.replace("/package.json", "/project.json");

When not to use it

In single-package repositories, or in monorepos where the task runner is configured centrally (e.g., a single turbo.json at the root) rather than per-package.