Nullish coalescing to ternaries

Option: transforms.nullishCoalescingToTernary

What it changes

Rewrites nullish-coalescing expressions as equivalent conditional expressions while evaluating the left operand once.

var x = a ?? b;
f(get() ?? fallback);

var x = a;
if (x === null ? true : x === void 0) x = b;
f(((_t = get()) !== null ? _t !== void 0 : false) ? _t : fallback);

Run this transform by setting transforms.nullishCoalescingToTernary to true:

obfuscate.mjs

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

Open the TypeScript implementation on GitHub.

Review behavior checks and cases this transform leaves alone.

Last modified on August 26, 2026