feat: add treeshake-check package, syncpack, and lefthook

Add @wolfcola/treeshake-check — a tree-shakeability analyzer built on
Effect and Rollup. Bundles a package as a side-effect-only import and
reports what Rollup couldn't eliminate, with AST-based cause detection.

Tooling:
- syncpack for dependency version consistency and catalog enforcement
- lefthook pre-commit hook: syncpack lint, eslint --fix, prettier --write
- .prettierignore and eslint ignores for fixtures and build output
- Add @effect/cli, @effect/platform, @effect/platform-node, @effect/vitest
  to workspace catalog; bump effect to ^3.21.1

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ryanbas21

.changeset/add-treeshake-check.md

@@ -0,0 +1,5 @@
+---
+'@wolfcola/treeshake-check': minor
+---
+
+Add treeshake-check package — a tree-shakeability analyzer for npm packages built on Effect and Rollup

.gitignore

@@ -9,3 +9,4 @@ elm-stuff/
 *.crx.zip
 *.zip
 packged/
+out-tsc/

.prettierignore

@@ -0,0 +1,7 @@
+dist
+node_modules
+coverage
+elm-stuff
+out-tsc
+pnpm-lock.yaml
+**/__fixtures__/bad-syntax/**

.syncpackrc.ts

@@ -0,0 +1,77 @@
+// @ts-check
+
+/** @type {import("syncpack").RcFile} */
+const config = {
+  sortFirst: [
+    'name',
+    'version',
+    'private',
+    'description',
+    'license',
+    'type',
+    'exports',
+    'main',
+    'types',
+    'bin',
+    'files',
+    'scripts',
+    'dependencies',
+    'devDependencies',
+    'peerDependencies',
+  ],
+  versionGroups: [
+    // ─── Ignore catalog source definitions ─────────────────────────────
+    // pnpm-workspace.yaml defines the actual versions — these are the
+    // source of truth for catalogs and should not be pinned.
+    {
+      label: 'Catalog source definitions are ignored',
+      packages: ['pnpm-workspace.yaml'],
+      isIgnored: true,
+    },
+    // ─── Ignore peer dependencies ──────────────────────────────────────
+    // Peer deps use semver ranges set by the consumer, not catalogs.
+    {
+      label: 'Peer dependencies are ignored',
+      dependencyTypes: ['peer'],
+      isIgnored: true,
+    },
+    // ─── Catalog enforcement: effect ecosystem ─────────────────────────
+    {
+      label: 'Effect packages must use catalog:effect',
+      dependencies: [
+        'effect',
+        '@effect/cli',
+        '@effect/platform',
+        '@effect/platform-node',
+        '@effect/vitest',
+      ],
+      pinVersion: 'catalog:effect',
+    },
+    // ─── Catalog enforcement: vitest ───────────────────────────────────
+    {
+      label: 'Vitest must use catalog:vitest',
+      dependencies: ['vitest'],
+      pinVersion: 'catalog:vitest',
+    },
+    // ─── Catalog enforcement: vite ─────────────────────────────────────
+    {
+      label: 'Vite must use catalog:vite',
+      dependencies: ['vite'],
+      pinVersion: 'catalog:vite',
+    },
+    // ─── Internal workspace deps ───────────────────────────────────────
+    {
+      label: 'Internal @wolfcola/* packages must use workspace:*',
+      dependencies: ['@wolfcola/*'],
+      pinVersion: 'workspace:*',
+    },
+    // ─── Banned packages ───────────────────────────────────────────────
+    {
+      label: '@effect/schema is deprecated — use effect/Schema',
+      dependencies: ['@effect/schema'],
+      isBanned: true,
+    },
+  ],
+};
+
+export default config;

eslint.config.mjs

@@ -19,6 +19,8 @@ export default [
       '**/coverage',
       '**/elm-stuff',
       '**/vite.config.*.timestamp*',
+      '**/__fixtures__/**',
+      '**/out-tsc/**',
     ],
   },
   ...compat.extends('plugin:@typescript-eslint/recommended', 'plugin:prettier/recommended'),
@@ -44,7 +46,6 @@ export default [
       '@typescript-eslint/no-use-before-define': 'warn',
       '@typescript-eslint/no-unused-vars': ['error', { ignoreRestSiblings: true }],
       'max-len': 'off',
-      quotes: ['error', 'single', { allowTemplateLiterals: true }],
     },
   },
   {

lefthook.yml

@@ -0,0 +1,15 @@
+pre-commit:
+  commands:
+    syncpack-lint:
+      run: pnpm syncpack lint
+      stage_fixed: true
+    eslint:
+      glob: '*.{js,mjs,ts,mts,tsx}'
+      exclude: '(out-tsc|__fixtures__|dist|node_modules)/'
+      run: pnpm eslint --no-warn-ignored --fix {staged_files}
+      stage_fixed: true
+    prettier:
+      glob: '*.{js,mjs,ts,mts,tsx,json,yaml,yml,md,css,html}'
+      exclude: '(out-tsc|__fixtures__/bad-syntax|dist|node_modules)/'
+      run: pnpm prettier --write {staged_files}
+      stage_fixed: true

package.json

@@ -20,23 +20,28 @@
     "test": "vitest run",
     "typecheck": "tsc --build",
     "changeset": "changeset",
-    "version": "changeset version",
-    "release": "pnpm build && changeset publish"
+    "version": "changeset version && prettier --write '**/package.json' pnpm-workspace.yaml",
+    "release": "pnpm build && changeset publish",
+    "syncpack:lint": "syncpack lint",
+    "syncpack:fix": "syncpack fix-mismatches",
+    "prepare": "test \"$CI\" = 'true' || lefthook install"
   },
   "devDependencies": {
     "@changesets/changelog-github": "^0.6.0",
     "@changesets/cli": "^2.27.9",
     "@eslint/eslintrc": "^3.0.0",
     "@eslint/js": "~9.39.0",
+    "@types/node": "^22.0.0",
     "@typescript-eslint/eslint-plugin": "^8.45.0",
     "@typescript-eslint/parser": "^8.45.0",
     "eslint": "^9.8.0",
     "eslint-config-prettier": "10.1.8",
     "eslint-plugin-import": "2.31.0",
     "eslint-plugin-prettier": "^5.2.3",
-    "@types/node": "^22.0.0",
     "jsdom": "^26.1.0",
+    "lefthook": "^2.1.6",
     "prettier": "^3.2.5",
+    "syncpack": "^15.1.2",
     "typescript": "5.8.3",
     "vite": "catalog:vite",
     "vitest": "catalog:vitest"

packages/treeshake-check/package.json

@@ -0,0 +1,41 @@
+{
+  "name": "@wolfcola/treeshake-check",
+  "version": "0.0.0",
+  "description": "Check whether a package can be fully tree-shaken by Rollup",
+  "license": "MIT",
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./dist/src/index.d.ts",
+      "import": "./dist/src/index.js",
+      "default": "./dist/src/index.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "main": "./dist/src/index.js",
+  "types": "./dist/src/index.d.ts",
+  "bin": {
+    "treeshake-check": "./dist/src/index.js"
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "tsc -p tsconfig.lib.json",
+    "lint": "eslint .",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "@effect/cli": "catalog:effect",
+    "@effect/platform": "catalog:effect",
+    "@effect/platform-node": "catalog:effect",
+    "@rollup/plugin-virtual": "^3.0.2",
+    "acorn": "^8.16.0",
+    "effect": "catalog:effect",
+    "rollup": "^4.59.0"
+  },
+  "devDependencies": {
+    "@effect/vitest": "catalog:effect",
+    "vitest": "catalog:vitest"
+  }
+}

packages/treeshake-check/src/__fixtures__/bad-syntax/index.js

@@ -0,0 +1 @@
+this is not valid javascript !!!###

packages/treeshake-check/src/__fixtures__/clean/index.js

@@ -0,0 +1,10 @@
+// Pure function exports — no side effects, fully tree-shakeable
+export function add(a, b) {
+  return a + b;
+}
+
+export function multiply(a, b) {
+  return a * b;
+}
+
+export const PI = 3.14159;