How to export variables named with hyphen in ESM

CJS

exports['foo-bar'] = {}  // -> OK

ESM

exports['foo-bar'] = {};        // -> NG
export['foo-bar'] = {};         // -> NG
export { 'foo-bar': {} };       // -> NG
export { fooBar as foo-bar };   // -> NG
export { fooBar as 'foo-bar' }; // -> NG

Normally I wouldn't do this, so it's not a problem, but I'm having trouble because Firebase Functions v2 only allows lowercase alphabets, numbers and hyphens in the name and requires that I export it.