JavaScript Obfuscation and Performance Issues

JavaScript obfuscation can indeed cause significant performance degradation in applications. When using tools like @rbf/parcel-optimizer-javascript-obfuscator, which leverages the javascript-obfuscator library, several factors could contribute to the performance drop you're experiencing with Mirrors:

Common Causes of Performance Issues After Obfuscation

1. Code Complexity Increase: Obfuscation typically adds layers of complexity to your code, including:

   • String transformations
   • Control flow flattening
   • Dead code injection
   • Variable name mangling

2. Runtime Overhead: Many obfuscation techniques add runtime overhead:

   • String arrays that require decoding at runtime
   • Self-defending mechanisms that check for tampering
   • Complex control flow that's harder for JavaScript engines to optimize

3. JIT Optimization Limitations: JavaScript engines can't optimize obfuscated code as effectively:

   • Function inlining becomes difficult
   • Type inference is less effective
   • Hidden class optimizations may fail

Potential Solutions

1. Adjust Obfuscation Settings: Try using less aggressive settings in your configuration:

   JAVASCRIPTCopied
   {
     "compact": true,
     "controlFlowFlattening": false,
     "deadCodeInjection": false,
     "stringArray": true,
     "stringArrayThreshold": 0.5, // Try lowering this
     "transformObjectKeys": false
   }

2. Selective Obfuscation: Only obfuscate parts of your code that need protection, not performance-critical sections.

3. Profile Before and After: Use browser developer tools to identify specific bottlenecks in the obfuscated code.

4. Consider Alternatives: Minification often provides sufficient protection with less performance impact.

Without more specific details about your Mirrors implementation, it's difficult to pinpoint the exact cause, but these are common issues when using JavaScript obfuscation tools.