bundle-cop-vercel-plugin

Next.js adapter that attributes client bundle cost to the importing source file and enforces size budgets during next build.

| | | |---|---| | Docs | bundle-cop.vercel.app/docs | | npm | bundle-cop-vercel-plugin | | Source | nad33mahm3d/bundle-cop-vercel-plugin (packages/vercel-plugin) | | Changelog | CHANGELOG.md | | Issues | GitHub Issues |

Part of Bundle Cop (adapter + Vercel integration app).

Requirements

• Next.js 16+ (adapterPath / Adapters API)
• Node.js 20+

Install

pnpm add bundle-cop-vercel-plugin
# npm i bundle-cop-vercel-plugin
# yarn add bundle-cop-vercel-plugin

Setup

// next.config.ts
import type { NextConfig } from 'next'
import { createRequire } from 'node:module'

const require = createRequire(import.meta.url)

const nextConfig: NextConfig = {
  adapterPath: require.resolve('bundle-cop-vercel-plugin/adapter'),
}

export default nextConfig

Use the /adapter export. Next loads adapters via require.resolve + ESM interop; the dedicated adapter entry exposes onBuildComplete correctly.

Optional budgets

Create bundle-cop.config.json in the project root:

{
  "budgets": [
    { "path": "/*", "maxSize": "250kb", "enforce": "warn" },
    { "path": "/dashboard", "maxSize": "400kb", "enforce": "error" }
  ],
  "ignore": [],
  "suggestions": true,
  "githubComment": true
}

• enforce: "warn" — logs over-budget routes
• enforce: "error" — fails the build

What it does

On onBuildComplete:

1. Parses .next diagnostics when present; otherwise uses route/chunk fallbacks (Turbopack-friendly)
2. Attributes known heavy packages (e.g. moment, lodash) to the importing source file
3. Enforces budgets from bundle-cop.config.json
4. Writes bundle-report.json (and under .vercel/output/static/ when possible)
5. Uploads a private Blob report when BLOB_READ_WRITE_TOKEN is set

Environment (optional)

| Variable | Purpose | |----------|---------| | BLOB_READ_WRITE_TOKEN | Upload private report to Vercel Blob | | VERCEL_GIT_COMMIT_SHA / GITHUB_SHA | Report key (commit SHA) |

Releases

Versions are published from GitHub Releases. Tag vX.Y.Z → CI publishes the same version to npm. See the repo README.

License

MIT