How to fix npm ERR! code ETOOLARGE npm ERR! Package size exceeds maximum allowed size in npm

# Preview files without publishing
npm pack --dry-run

# Create tarball locally to inspect
npm pack

# List tarball contents
tar -tzf my-package-1.0.0.tgz | head -50

# Check tarball size
ls -lh *.tgz

{
  "name": "my-package",
  "version": "1.0.0",
  "files": [
    "dist/",
    "lib/",
    "index.js"
  ]
}

# .npmignore

# Version control
.git
.gitignore

# Dependencies (auto-ignored but explicit)
node_modules/

# Testing
test/
__tests__/
*.test.js
coverage/

# Development
.env
.vscode/
tsconfig.json
webpack.config.js

# Source maps
*.map

# CI/CD
.github/
.travis.yml

# Create tarball
npm pack

# Check file count
tar -tzf *.tgz | wc -l

# Check size
ls -lh *.tgz

# Extract and inspect
tar -xzf *.tgz
ls -la package/

{
  "files": [
    "dist/index.js",
    "dist/index.d.ts"
  ]
}

*.map

{
  "scripts": {
    "prepublishOnly": "npm pack --dry-run && npm run build"
  }
}

npm install --save-dev size-limit @size-limit/file

{
  "size-limit": [
    {
      "path": "dist/index.js",
      "limit": "100 KB"
    }
  ]
}