By default, performance.now() gives us millisecond precision. It can, however, go up to microsecond precision once --allow-hrtime option is provided.
Which is not, by default. They say it’s somehow related to security, blah, blah, Spectre can be exploited if a fine timer is available.
What’s fairly disrupting is that interactive deno works with hi-res timer turned on. Took me a bit of an effort and time to find that out.