npm-tariff

A “trade-war simulator” for Node.js.
Inject delays, quotas, and comedic messages when importing packages – as if they’re being taxed at customs. ~~> WARNING: This is purely satire and not recommended for production. Unless you enjoy forging comedic chaos in your CI pipeline!~~

Features

• Tariff Delays
  Slow down imports of specific packages with an artificial “tariff” percentage.
• Import Quotas
  Enforce a max number of times you can require a certain package. Exceed it, face an “import privilege revoked” message, and an exit(1).
• Single Tweet
  At the end of the script, print one random ASCII tweet about tariffs, instead of spamming logs for each import.
• Trade‑Deficit Dashboard
  On exit, show a summary of:
  • Which packages you “taxed” or “capped”
  • Total base load time vs. total artificially delayed time
  • A final comedic remark

Installation

npm install npm-tariff

Or if you’d rather link it during local dev:

# In your clone of npm-tariff
npm link

# In your test project
npm link npm-tariff

Usage

1. Opt-In via --require
   Run your code like so, ensuring it’s required before your code:

   node --require npm-tariff yourScript.js

   This preloads npm-tariff, letting it monkey‑patch the loader.

2. Programmatic API
   In your script, you can do:

   const tariff = require('npm-tariff');
      
   // Tariffs
   tariff.setTariffs({
     lodash: 100, // 100% => artificially adds 100 ms (by default) 
     axios: 200   // 200% => 200 ms
   });
      
   // Quotas
   tariff.setQuota({
     lodash: 2    // only allow requiring 'lodash' 2 times
   });
      
   // If you haven't already preloaded it via --require,
   // enable the monkey-patch manually:
   tariff.enable();
   
   console.log('--- Importing lodash first time ---');
   require('lodash');
   
   console.log('--- Importing axios ---');
   require('axios');
   
   console.log('--- Importing lodash second time ---');
   require('lodash');
   
   console.log('--- Importing lodash third time (should fail) ---');
   require('lodash');

3. Auto‑enable
   By default, if npm-tariff is loaded before your main code (via --require), it automatically calls enable() so you don’t have to.

Demo

node --require npm-tariff demo.js

Possible Output:

--- Importing lodash first time ---
🛃  [npm‑tariff] Applying 100% tariff on "lodash" (100ms)
🕒  Base: 12ms → After tariff: 112ms (delay = 100ms)
--- Importing axios ---
🛃  [npm‑tariff] Applying 200% tariff on "axios" (200ms)
🕒  Base: 46ms → After tariff: 246ms (delay = 200ms)
--- Importing lodash second time ---
🛃  [npm‑tariff] Applying 100% tariff on "lodash" (100ms)
🕒  Base: 1ms → After tariff: 101ms (delay = 100ms)
--- Importing lodash third time (should fail) ---

❌  [npm‑tariff] Import quota exceeded for "lodash"
    Allowed: 2, Attempted: 3
    Your import privileges have been revoked. 🇺🇸💼

================ Trade‑Deficit Dashboard ================
lodash          x2  | base: 13ms | delay: 200ms
axios           x1  | base: 46ms | delay: 200ms
--------------------------------------------------------
   Grand Base Time : 59 ms
   Grand Delay     : 400 ms
========================================================

🗣️  Final Word On Tariffs: (ง'̀-'́)ง  WE'RE GONNA MAKE IMPORTS GREAT AGAIN!

API

interface Tariff {
  setTariffs(table: Record<string, number>): void;
  setQuota(table: Record<string, number>): void;
  enable(): void;
  disable(): void;
}

| Method | Description | |-------------:|:-----------------------------------------------------------------| | setTariffs | Provide a mapping: { pkgName: percentage }. 100 means +100ms. | | setQuota | Provide a mapping: { pkgName: maxImports }. Exceed = error. | | enable | Monkey‑patch Node’s loader, applying tariffs & quotas. | | disable | Revert to Node’s standard loader. No more import overhead. |

FAQ

1. Why block the event loop with synchronous sleeps?
   If you actually wanted to do something useful, an async approach might be better.

2. Why do I see random internal Node modules in the dashboard?
   We intentionally filter them out in the newest version, but if you do see them, it’s because Node is requesting internal modules. To hide them, only track stats for the modules you explicitly tariff/quota.

3. Safe for production?
   Absolutely not recommended. Use at your own risk.

4. What’s with the “import privileges have been revoked” message?
   That’s the point its called “quota limit.”

Contributing

Feel free to open issues or PRs to:

• Add more comedic ASCII art
• Adjust the base latency or randomize it
• Add more “trade policy” toggles (like weekend surcharges, random “trade embargo” errors, etc.)

License

MIT – Because everyone wants stuff to be free. Enjoy your tariff wars!