According to the Node.js v14 release notes, node.green, and my own testing, the ES2020 nullish coalescing operator (??) (TC39 proposal) is supported by Node.js v14 and later. However, [email protected] does not warn when it is used in packages where engines.node includes lower versions. It would be great if ?? could be added to no-unsupported-features/es-syntax.

Thanks for considering,
Kevin