Remove unreachable code

Option: transforms.removeUnreachableCode

What it changes

Removes unreachable statements that follow unconditional control flow while retaining declarations whose hoisting can still be observed.

function foo() {
  return "bar";
  log("baz");
}

function foo() {
  return "bar";
}

Run this transform by setting transforms.removeUnreachableCode to true:

obfuscate.mjs

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

Open the TypeScript implementation on GitHub.

Review behavior checks and cases this transform leaves alone.

Last modified on August 26, 2026