This feature enables developers to make their numeric literals more readable by creating a visual separation between groups of digits. Using underscores (_, U+005F) as separators helps improve readability for numeric literals, for ex: 1_000_000_000.
Docs: https://v8.dev/features/numeric-separators
Samples: https://v8.dev/features/numeric-separators http://2ality.com/2018/02/numeric-separators.html