Arguments to parameters

Option: transforms.argumentsToParameters

What it changes

Replaces eligible numeric arguments[i] reads with the corresponding parameter in sloppy functions with simple parameter lists.

function foo(bar) {
  log(arguments[0]);
}

function foo(bar) {
  log(bar);
}

Run this transform by setting transforms.argumentsToParameters to true:

obfuscate.mjs

const output = obfuscate(source, {
  transforms: {
    argumentsToParameters: true,
  },
})

Open the TypeScript implementation on GitHub.

Review behavior checks and cases this transform leaves alone.

Last modified on August 26, 2026