gandalf-gate: guard + gatekeeper utilities

README.md

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-# gandalf-gate
-
-A tiny guard utility — you shall not pass invalid input.
+# gandalf-gate 🧙
+A tiny guard utility.
+```js
+const { youShallNotPass, gatekeeper } = require('@community/gandalf-gate');
+youShallNotPass(user.isAdmin, 'admins only');
+const gate = gatekeeper(3); // allow 3, then throws
+```

gate.js

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+// gandalf-gate — a tiny guard utility. "You shall not pass" invalid input.
+function youShallNotPass(condition, message = 'You shall not pass!') {
+  if (!condition) throw new Error(message);
+}
+// A simple gatekeeper: allow at most `max` calls, then refuse.
+function gatekeeper(max) {
+  let count = 0;
+  return () => { if (count++ >= max) throw new Error('You shall not pass! (limit reached)'); };
+}
+module.exports = { youShallNotPass, gatekeeper };

package.json

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+{ "name": "@community/gandalf-gate", "version": "1.0.0", "main": "gate.js", "license": "MIT",
+  "description": "A tiny guard utility — you shall not pass invalid input." }

test.sh

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+#!/bin/bash
+node -e "const {youShallNotPass,gatekeeper}=require('./gate'); youShallNotPass(true); let g=gatekeeper(1); g(); try{g();process.exit(1)}catch{console.log('ok')}"