Special values to strings

Option: transforms.specialsToStrings

What it changes

Rewrites true, false, NaN, undefined, and Infinity as equivalent expressions built from strings.

if (x === undefined) return NaN;
var lim = !done ? Infinity : 0;
var flag = !x ? true : false;

if (x === void "ab") return +"cd";
var lim = !done ? 1 / !"ef" : 0;
var flag = !x ? !!"gh" : !"ij";

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

obfuscate.mjs

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

Pass { stringGeneratorMode } instead of true to override its generated string style.

Open the TypeScript implementation on GitHub.

Review behavior checks and cases this transform leaves alone.

Last modified on August 26, 2026