Pack into a Function constructor

Option: transforms.pack

What it changes

Serializes the program and executes it through a generated Function constructor.

pack runs the generated string as a Function body. import.meta and top-level await are syntax errors there. A top-level arguments refers to the generated function. pack rejects export statements before producing output.

Before and after

console.log(value);

Function("M", "console.log(M[\"b\"]);")({
  get "b"() {
    return value;
  }
});

Configuration

Run this transform by setting transforms.pack to true or an options object:

obfuscate.mjs

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

Pass { escapeStrict, skipGlobals, stringGeneratorMode } instead of true. escapeStrict removes strict mode from the generated function. skipGlobals defaults to true, which leaves standard globals as direct references. Set it to false to route every free name through accessors. An array replaces the default list. Every listed name must be visible inside a generated Function.

View the implementation

Open the TypeScript implementation on GitHub.

Read the behavior tests

Review behavior checks and cases this transform leaves alone.

Last modified on August 29, 2026

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Reference

Support

Pack into a Function constructor

What it changes

Before and after

Configuration

View the implementation

Read the behavior tests

​What it changes

​Before and after

​Configuration

View the implementation

Read the behavior tests

What it changes

Before and after

Configuration