Improve Zero Width identifier generator

Author: MichaelXF

CHANGELOG.md

@@ -16,6 +16,8 @@ Option values: `true/false`
 
 [Learn more here.](/docs/TamperProtection.md)
 
+---
+
 - `Rename Variables` improvements:
 
 - - New `__JS_CONFUSER_VAR__` function to access renamed variables. [Learn more here](/docs/RenameVariables.md).
@@ -31,9 +33,8 @@ var CA1HU0 = 'John Doe';
 eval('console.log(' + 'CA1HU0' + ')');
 ```
 
+- Improved the `Zero Width` identifier generator (Thanks @doctor8296!)
 
-- Fix [#134](https://github.com/MichaelXF/js-confuser/issues/134)
-- - Detect tampering to the Global Object with the new `lock.tamperProtection` option.
 
 # `1.7.2`
 Updates

src/transforms/transform.ts

@@ -8,7 +8,9 @@ import {
 import {
   alphabeticalGenerator,
   choice,
+  createZeroWidthGenerator,
   getRandomInteger,
+  shuffle,
 } from "../util/random";
 import { ok } from "assert";
 import Obfuscator from "../obfuscator";
@@ -87,6 +89,8 @@ export default class Transform {
 
   initVariables = new Map<string, string>();
 
+  zeroWidthGenerator = createZeroWidthGenerator();
+
   constructor(obfuscator, priority: number = -1) {
     ok(obfuscator instanceof Obfuscator, "obfuscator should be an Obfuscator");
 
@@ -312,49 +316,7 @@ export default class Transform {
               return "var_" + count;
 
             case "zeroWidth":
-              var keyWords = [
-                "if",
-                "in",
-                "for",
-                "let",
-                "new",
-                "try",
-                "var",
-                "case",
-                "else",
-                "null",
-                "break",
-                "catch",
-                "class",
-                "const",
-                "super",
-                "throw",
-                "while",
-                "yield",
-                "delete",
-                "export",
-                "import",
-                "public",
-                "return",
-                "switch",
-                "default",
-                "finally",
-                "private",
-                "continue",
-                "debugger",
-                "function",
-                "arguments",
-                "protected",
-                "instanceof",
-                "function",
-                "await",
-                "async",
-              ];
-
-              var safe = "\u200C".repeat(count + 1);
-
-              var base = choice(keyWords) + safe;
-              return base;
+              return this.zeroWidthGenerator.generate();
           }
 
           throw new Error("Invalid 'identifierGenerator' mode: " + mode);

src/util/random.ts

@@ -139,3 +139,83 @@ export function alphabeticalGenerator(index: number) {
   }
   return name;
 }
+
+export function createZeroWidthGenerator() {
+  var keywords = [
+    "if",
+    "in",
+    "for",
+    "let",
+    "new",
+    "try",
+    "var",
+    "case",
+    "else",
+    "null",
+    "break",
+    "catch",
+    "class",
+    "const",
+    "super",
+    "throw",
+    "while",
+    "yield",
+    "delete",
+    "export",
+    "import",
+    "public",
+    "return",
+    "switch",
+    "default",
+    "finally",
+    "private",
+    "continue",
+    "debugger",
+    "function",
+    "arguments",
+    "protected",
+    "instanceof",
+    "await",
+    "async",
+
+    // new key words and other fun stuff :P
+    "NaN",
+    "undefined",
+    "true",
+    "false",
+    "typeof",
+    "this",
+    "static",
+    "void",
+    "of",
+  ];
+
+  var maxSize = 0;
+  var currentKeyWordsArray: string[] = [];
+
+  function generateArray() {
+    var result = keywords
+      .map(
+        (keyWord) =>
+          keyWord + "\u200C".repeat(Math.max(maxSize - keyWord.length, 1))
+      )
+      .filter((craftedVariableName) => craftedVariableName.length == maxSize);
+
+    if (!result.length) {
+      ++maxSize;
+      return generateArray();
+    }
+
+    return shuffle(result);
+  }
+
+  function getNextVariable(): string {
+    if (!currentKeyWordsArray.length) {
+      ++maxSize;
+      currentKeyWordsArray = generateArray();
+    }
+    return currentKeyWordsArray.pop();
+  }
+
+  return { generate: getNextVariable };
+}

test/transforms/identifier/renameVariables.test.ts

@@ -509,7 +509,14 @@ test.each(["hexadecimal", "mangled", "number", "zeroWidth"])(
       `
   var myVar1 = "Correct Value";
 
-  TEST_OUTPUT = myVar1;
+  function myFunction(myVar2){
+      myVar2 = myVar1;
+      let myVar3 = myVar2;
+      var myVar4 = myVar3;
+      return myVar4;
+  }
+
+  TEST_OUTPUT = myFunction();
   `,
       {
         target: "node",