⚡ fast-ncu

An extremely fast, lightweight, and zero-configuration alternative to npm-check-updates (ncu). It checks your package.json dependencies against the npm registry concurrently and upgrades them to the latest versions.

🚀 More than 3x faster than the original npm-check-updates on cold runs, and up to 300x faster on cached runs!

⚡ Performance Comparison (Benchmark)

Tested on a repository containing 78 dependencies (the npm-check-updates codebase itself):

| Tool | Concurrency | Cache | Time (Seconds) | Speedup | | :--- | :--- | :--- | :--- | :--- | | 🐢 Original ncu | Default | N/A | 2.75s | Baseline | | ⚡ fast-ncu (Cold) | 15 (Default) | Disabled | 2.70s | 1.0x | | 🚀 fast-ncu (Cold) | 30 | Disabled | 0.88s | 3.1x faster | | 🛸 fast-ncu (Warm) | 30 | Enabled (Hit) | 0.01s (10ms) | 275x faster |

🛠️ How it works (Why it's so fast)

Most developers don't realize how much overhead goes into checking package versions. Here is how fast-ncu achieves extreme performance:

1. Tiny payloads via /latest CDN Edge Endpoint

• The Problem: Normal tools query https://registry.npmjs.org/<pkg> which returns the full package metadata (all historical versions, SHAs, dates, and readmes). For packages like typescript or aws-sdk, this JSON can be several megabytes.
• The Solution: We query https://registry.npmjs.org/<pkg>/latest. This returns a tiny, CDN-cached JSON object containing only the latest version details (~2KB). Our benchmarks show that the /latest endpoint is over 4x faster to resolve than the standard packument endpoint.

2. High-Performance Concurrency Limiter

• We developed an optimized, zero-dependency concurrency queue controller. It runs async HTTP requests in parallel with an adjustable limit (e.g. --concurrency 30), maximizing your network bandwidth without causing socket exhaustion or registry rate limits.

3. Ultra-Fast Startup Time (ESM + Zero Bloat)

• By avoiding heavy CLI packages (like yargs, commander) and bulky utilities (like chalk), the entire Node.js runtime boots and prints output in under 40ms. We use native ES Modules and picocolors (which starts up instantly and has zero dependencies).

4. Smart Local Caching Layer

• Subsequent runs are instantaneous. It safely stores the fetched versions in your system's temp directory (/tmp/fast-ncu-cache.json) for 5 minutes (configurable). A second run takes 10ms to check any number of packages!

📦 Installation

Run it on the fly using npx:

# Using fast-ncu
npx fast-ncu

# Or using the shorthand alias
npx fncu

Or install globally:

npm install -g fast-ncu

Once globally installed, you can use the command fast-ncu or its convenient shorthand fncu.

🚀 Usage

You can use the full name fast-ncu or the shorter shorthand fncu interchangeably:

# Check dependencies for updates (Safe - read only)
fncu

# Overwrite package.json with the upgraded versions
fncu -u

# Maximize speed by raising concurrency
fncu --concurrency 30

# Force bypass the cache
fncu --no-cache

⚙️ Options

• -u, --upgrade Overwrite package.json with upgraded versions
• --concurrency <num> Number of concurrent registry requests (default: 15)
• --no-cache Disable local caching
• -v, --version Show version of fast-ncu / fncu
• -h, --help Show help

🧪 Tests

The project includes unit tests using Node's native test runner (zero external testing dependencies).

To compile and run tests:

npm run build
npm test

📄 License

MIT