Adding Lib Code

Author: cttricks

.npmignore

@@ -0,0 +1,19 @@
+# Ignore dev and build configs
+rollup.config.js
+*.log
+
+# Ignore local test files
+.test/
+
+# Ignore everything not needed in the final npm package
+.gitignore
+*.md
+example/
+examples/
+
+# Ignore dev-specific files
+.vscode/
+.idea/
+
+# Ignore node_modules (shouldn't be included anyway)
+node_modules/

dist/pseudocrypt.min.js

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+/**
+ * PseudoCrypt — Short, reversible, pseudo-unique hashes for numeric values.
+ * Inspired by KevBurnsJr's original PHP implementation: 
+ * https://web.archive.org/web/20130727034425/http://blog.kevburnsjr.com/php-unique-hash
+ *
+ * Author: Tanish Raj (@cttricks)
+ * License: MIT
+ * Repository: https://github.com/cttricks/pseudocrypt
+ *
+ * This module provides two main functions:
+ * - encode: Convert a number into a pseudo-unique base62-like string
+ * - decode: Retrieve the original number from the encoded string
+ *
+ * ⚠️ Not cryptographically secure. Use only for ID obfuscation, pretty URLs, etc.
+ */
+
+const goldenPrimes = {
+    1: '1',
+    41: '59',
+    2377: '1677',
+    147299: '187507',
+    9132313: '5952585',
+    566201239: '643566407',
+    35104476161: '22071637057',
+    2176477521929: '294289236153',
+    134941606358731: '88879354792675',
+    8366379594239857: '7275288500431249',
+    518715534842869223: '280042546585394647'
+};
+
+const chars62 = [
+    ...Array.from({ length: 10 }, (_, i) => 48 + i), // 0-9
+    ...Array.from({ length: 26 }, (_, i) => 65 + i), // A-Z
+    ...Array.from({ length: 26 }, (_, i) => 97 + i)  // a-z
+];
+
+const base62 = (int) => {
+    int = BigInt(int);
+    let str = '';
+    const base = BigInt(62);
+    while (int > 0) {
+        const mod = int % base;
+        str += String.fromCharCode(chars62[Number(mod)]);
+        int = int / base;
+    }
+    return str.split('').reverse().join('');
+};
+
+const unBase62 = (str) => {
+    return [...str].reverse().reduce((acc, char, i) => {
+        const val = BigInt(chars62.indexOf(char.charCodeAt(0)));
+        return acc + val * (BigInt(62) ** BigInt(i));
+    }, BigInt(0));
+};
+
+/**
+ * Encodes a number into a short, base62-like hash string.
+ * Useful for generating pseudo-unique, URL-safe identifiers.
+ *
+ * @param {number | string | bigint} num - The numeric value to encode.
+ * @param {number} [len=5] - The desired length of the output hash. Must be between 1 and 10.
+ * @returns {string} Encoded hash string.
+ *
+ * @example
+ * const shortId = encode(123456); // e.g. "4Gze1"
+ */
+
+const encode = (num, len = 5) => {
+    num = BigInt(num);
+    const ceil = BigInt(62) ** BigInt(len);
+    const prime = BigInt(Object.keys(goldenPrimes)[len]);
+    const hashed = (num * prime) % ceil;
+    return base62(hashed).padStart(len, '0');
+};
+
+/**
+ * Decodes a hash string back into its original numeric value.
+ *
+ * @param {string} hash - The encoded hash string (must be generated by `encode()`).
+ * @returns {bigint} Original numeric value.
+ *
+ * @example
+ * const original = decode("4Gze1"); // 123456n
+ */
+const decode = (hash) => {
+    const len = hash.length;
+    const ceil = BigInt(62) ** BigInt(len);
+    const mmi = BigInt(Object.values(goldenPrimes)[len]);
+    const val = unBase62(hash);
+    return (val * mmi) % ceil;
+};
+
+module.exports = { encode, decode };

dist/pseudocrypt.min.js.map

@@ -8,6 +8,7 @@
     ".": "./index.js"
   },
   "scripts": {
+    "build": "rollup -c",
     "test": "node .test/index.js"
   },
   "repository": {
@@ -37,5 +38,9 @@
   "homepage": "https://github.com/cttricks/pseudocrypt#readme",
   "engines": {
     "node": ">=12"
+  },
+  "devDependencies": {
+    "rollup": "^2.79.2",
+    "rollup-plugin-terser": "^7.0.2"
   }
-}
+}

index.js

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+import { terser } from "rollup-plugin-terser";
+
+export default {
+    input: "index.js",
+    output: {
+        file: "dist/pseudocrypt.min.js",
+        format: "umd",
+        name: "PseudoCrypt",
+        exports: "named",
+        sourcemap: true
+    },
+    plugins: [terser()]
+};