edge-sentry-cli

Catch Node-only APIs in Edge/serverless code before they hit prod.

Not affiliated with Sentry (the error tracker).

Why

Edge runtimes (Vercel Edge Runtime, Cloudflare Workers, Deno Deploy, etc.) don’t ship Node’s standard library. A single fs import or process.env access hidden deep in a transitive dependency can:

• Crash requests at runtime
• Force your app to fall back to slower Node regions
• Break SSR/ISR paths that claim runtime: 'edge'

edge-sentry-cli statically scans your code and dependency graph, flags Node-only usage, and suggests Edge-safe fixes.

What it catches (rules)

• node-builtins → importing Node core modules (e.g. fs, path, crypto, stream, net, tls, http, https, zlib, child_process, cluster, worker_threads, dgram, dns, readline, repl, vm, perf_hooks, os, tty, module, url via node:url, etc.)
• node-globals → usage of process, Buffer (Node polyfill), global, global.require, __dirname, __filename in Edge-targeted code
• dynamic-require → require(expr) with non-literal, or CommonJS interop that forces Node resolution
• cjs-in-edge → importing CJS-only packages from Edge entrypoints (many Edge bundlers require ESM)
• transitive-builtins → dependencies that import Node builtins anywhere in their tree
• polyfill-leak (warn) → reliance on bundler polyfills not available at runtime (e.g. events, buffer)

Targets tune rule strictness. Example: global crypto.subtle is OK (Web Crypto) but import 'crypto' (Node) is not.

Quick start

# Install
npm i -D edge-sentry-cli
# or
yarn add -D edge-sentry-cli
# or
pnpm add -D edge-sentry-cli

# Zero-config scan (auto-detects frameworks and Edge entrypoints)
edge-sentry-cli scan

# With a config file
edge-sentry-cli scan -c edgesentry.config.json

Recommended npm script

{
  "scripts": {
    "edge:scan": "edge-sentry-cli scan --ci"
  }
}

Example output

edge-sentry-cli v0.1.0 • target(s): vercel-edge, cloudflare-workers
Scanning 231 files, 417 modules…

✖ 3 violations (2 error, 1 warn)

src/lib/upload.ts:12  node-builtins(fs)
  Importing "fs" is not allowed in Edge targets (vercel-edge, cloudflare-workers).
  10 | import fs from 'fs'
     |            ^^^^^^^
  11 | import { put } from '@vercel/blob'
  12 | // …

src/auth/session.ts:4  node-globals(process.env)  (warn)
  `process.env` is not available in Edge. Use platform secrets / runtime bindings.

node_modules/somepkg/index.js → transitive-builtins(crypto)
  Dependency "[email protected]" imports Node's "crypto". Replace or move usage off Edge.

Exit code: 1 (error violations found)

Configuration

Create edgesentry.config.json (or .yaml).

{
  "$schema": "https://unpkg.com/edge-sentry-cli/schema.json",
  "targets": ["vercel-edge", "cloudflare-workers"],
  "entry": [
    "app/**",
    "src/**",
    "middleware.{ts,tsx,js}"
  ],
  "ignore": ["**/*.test.*", "**/*.stories.*", "scripts/**"],
  "rules": {
    "node-builtins": "error",
    "node-globals": "error",
    "dynamic-require": "warn",
    "cjs-in-edge": "warn",
    "polyfill-leak": "warn"
  },
  "allow": {
    "modules": [],
    "globals": []
  },
  "resolve": {
    "tsconfig": "./tsconfig.json",
    "alias": {
      "@": "./src"
    }
  },
  "output": {
    "format": "pretty",
    "sarifFile": "./reports/edge-sentry.sarif"
  },
  "ci": {
    "failOn": "warn"
  }
}

Targets

• vercel-edge – forbids all Node core modules/globals
• cloudflare-workers – forbids all Node core modules/globals
• deno-deploy – forbids Node core modules (unless using Deno's Node-compat, which is discouraged for Edge paths)
• generic-edge – strict superset (default when unknown)

You can list multiple targets. The strictest rule wins.

CLI

Usage: edge-sentry [command] [options]

Commands:
  scan                 Scan files & deps for Edge-incompatible code
  explain <id>         Explain a rule or violation id with suggestions
  list-targets         Print built-in targets and their constraints
  print-config         Show the resolved config

Options:
  -c, --config <file>  Path to config file
  -p, --paths <globs>  Glob(s) to scan (overrides config.entry)
  --format <fmt>       pretty | json | sarif (default: pretty)
  --fail-on <level>    none | warn | error (CI-friendly)
  --cache              Enable disk cache (default on in CI)
  --max-warnings <n>   Fail if warnings exceed n
  -q, --quiet          Only print violations
  -v, --verbose        Debug logging
  -h, --help           Show help

Exit codes

• 0 – no violations
• 1 – error-level violations found
• 2 – internal error (crash, bad config)

How it works

• Graph walker (ESM + CJS) using a fast parser to resolve imports from your entrypoints
• Heuristic target model that encodes what each Edge runtime exposes
• Rule engine that matches imports, globals, and call sites
• Transitive analysis: dives into node_modules (respects exports/conditions)
• Cache keyed by file content + lockfile to make re-runs cheap

No bundling; purely static analysis. Zero runtime hooks.

Framework recipes

Next.js (App Router)

• Add "edge:scan": "edge-sentry-cli scan --paths app/** middleware.ts" to your scripts
• Edge hints auto-detected in:
  • export const runtime = 'edge' in route handlers
  • middleware.ts
• Common fixes:
  • Replace import crypto from 'crypto' with globalThis.crypto.subtle
  • Move Node-only code to route.ts with export const runtime = 'nodejs' or to server actions executed on Node

Cloudflare Workers

• Use platform bindings for secrets; avoid process.env
• Use Web Crypto / TextEncoder / ReadableStream

Suggested fixes (cheatsheet)

| Node thing | Why it breaks on Edge | Edge-safe alternative | Example fix | |---|---|---|---| | import fs from 'fs' | No filesystem | Use KV/blob/HTTP, or move to Node runtime | Use platform storage (Blob, KV) | | import crypto from 'crypto' | Node module missing | globalThis.crypto.subtle | await crypto.subtle.digest('SHA-256', data) | | process.env.X | process undefined | Platform secrets / env bindings | Inject via runtime env/bindings | | Buffer.from() | Node Buffer polyfill missing | TextEncoder / Uint8Array | new TextEncoder().encode(str) | | path.join() | Node path module missing | URL/strings | new URL('./file', import.meta.url) | | CJS-only deps | Edge bundlers prefer ESM | Choose ESM build or alt package | import { ... } from 'pkg/esm' |

CI integration

GitLab CI (recommended)

edge_scan:
  stage: test
  image: node:20-alpine
  script:
    - corepack enable
    - yarn install --immutable --prefer-offline
    - yarn edge:scan --format sarif --fail-on error
  artifacts:
    when: always
    paths:
      - reports/edge-sentry.sarif
    expire_in: 1 week
  allow_failure: false

GitHub Actions

- name: Edge safety scan
  run: |
    corepack enable
    yarn install --immutable --prefer-offline
    yarn edge:scan --format sarif --fail-on error

Programmatic API (optional)

import { scan } from 'edge-sentry-cli';

const result = await scan({
  targets: ['vercel-edge'],
  entry: ['app/**', 'middleware.ts'],
});

if (result.errors.length) process.exit(1);

Limitations

• Static analysis ≠ full runtime: can’t detect platform quota limits, CPU timeouts, or non-standard shims
• Some packages ship mixed ESM/CJS; detection may be conservative (warns instead of errors)
• Polyfills vary by bundler; prefer explicit configuration if you intentionally include one

Roadmap

• ✅ v0: core rules, JSON/SARIF output, GitLab-friendly exit codes
• 🔜 Codemods (auto-replace Node APIs with Edge equivalents where safe)
• 🔜 PR/MR annotations (GitLab/GitHub) with inline comments
• 🔜 Suggested replacements registry (community-maintained)
• 🔜 VS Code problem matcher + ESLint rule bridge
• 🔜 Caching by workspace graph (Turborepo/Changesets-aware)

Contributing

• Issues & PRs welcome
• Please include a failing fixture for rule changes
• Run tests with pnpm test / yarn test

License

MIT © You and contributors