Your Edge entry doesn’t fail the build. It just gets slower every PR. This rule fails the PR instead.

One convenient import in middleware.ts or Next 16 proxy.ts can drag in node:fs three files deep — or a 400KB local graph — while next build still passes. This plugin fails that PR in the editor / CI, on the entry import, with the chain.

The squiggle sits on ./lib/notify — not on a leaf deep in the tree. That is the point.

Before / after

// ❌ proxy.ts — “just reuse notify”
import { notify } from "./lib/notify";

// ✅ proxy.ts — thin Edge slice
import { notifyEdge } from "./lib/notify-edge";

Banning fs on the entry file is not enough. The leak is almost always transitive. Byte bloat happens even when nothing Node-shaped shows up — so there is a graph size budget too.

Install

pnpm add -D eslint-plugin-next-edge-boundary

Peer: eslint >=9. Optional: typescript.

Flat config

import nextEdgeBoundary from "eslint-plugin-next-edge-boundary";

export default [
  {
    files: ["middleware.ts", "src/middleware.ts", "proxy.ts", "src/proxy.ts"],
    ...nextEdgeBoundary.configs.recommended,
  },
];

Use configs.strict for a 32 KiB budget and barrels as errors. Legacy eslintrc: configs["recommended-legacy"] / configs["strict-legacy"].

Rules

| Rule | What it catches | | ------------------------------------ | ------------------------------------------------------------------------------------------------------------------ | | next-edge-boundary/no-node-apis | Value-import graph reaches Node builtins (fs / node:fs, …) or a denylist package (sharp, pg, mongodb, …) | | next-edge-boundary/max-graph-bytes | Estimated local source graph exceeds the budget (64 KiB recommended, 32 KiB strict) | | next-edge-boundary/no-barrels | Entry imports of barrels (@/lib, @/utils, …) or import * as namespaces |

import type / export type are ignored — they erase at compile time.

recommended vs strict

| | recommended | strict | | ----------------- | -------------------- | -------------------- | | no-node-apis | error | error | | max-graph-bytes | error · max: 65536 | error · max: 32768 | | no-barrels | warn | error |

Why not no-restricted-imports / Next build alone

| Approach | Gap | | ----------------------- | ----------------------------------------------------------------------------------------- | | no-restricted-imports | Direct specifiers only. No transitive walk, no size budget, no chain. | | Next / Edge build | Often fails late, and mainly on hard Node APIs. Quiet size regression can ship for weeks. | | This plugin | Transitive graph + byte budget + chain on the entry import, at lint time. |

Options

Shared on every rule:

{
  allowModules?: string[];
  denyModules?: string[];
  ignorePatterns?: string[];
  tsconfigPath?: string;
  allowImportChains?: string[][]; // last resort
}

max-graph-bytes: max, includeNodeModules, packageWeights
no-barrels: barrelPatterns, forbidNamespaceImports

Entrypoints

Matched by basename: middleware.ts / .js, proxy.ts / .js (Next.js 16). Scope them with ESLint files as above.

Limitations

• Dynamic import() is ignored in v1
• Not a bundler — local source byte estimate, not Turbopack/webpack output
• App Router export const runtime = 'edge' detection is not in v1

License

MIT