Mangling

Oxc minifier supports mangling variable names and private class fields.

This feature is enabled by default and can be disabled by setting the mangle option to false.

Top Level Variables

Top level variables are not mangled by default for non module code. You can enable mangling for top level variables by setting the mangle.toplevel option to true.

// input
var foo = 1;

// output
var e = 1;

// Example
import { minify } from "oxc-minify";

const result = await minify("lib.js", code, {
  module: false, // non-module code
  compress: {
    mangle: {
      toplevel: true,
    },
  },
});

Keep name Property Values

Mangling variable names can change the name property values of functions / classes. You can keep the original name property values by enabling the mangle.keepNames option.

// input
var foo = function () {};

// output
var foo = function () {};

// Example
import { minify } from "oxc-minify";

const result = await minify("lib.js", code, {
  compress: {
    mangle: {
      keepNames: true, // shorthand of { function: true, class: true }
    },
  },
});

compress.keepNames option

When enabling this option, you may also want to enable the compress.keepNames option.

Debugging The Mangler

To debug the mangler, you can enable the mangle.debug option. When this option is enabled, the mangler will use slot_0, slot_1, ... as variable names.

// input
var foo = 1;

// output
var slot_0 = 1;

// Example
import { minify } from "oxc-minify";

const result = await minify("lib.js", code, {
  compress: {
    mangle: {
      debug: true,
    },
  },
});