Fastest and lightest way to get the current time in milliseconds with JS Date object

Question

There are different ways to get the current time in milliseconds with Date object:

(new Date()).getTime();
+new Date();
Date.now();

Assuming that you don't need to create an object and just need a current time in milliseconds, which one would be the most effective one? In terms of performance.

EDIT: I understand most devs wouldn't care about this, but it may matter when you work in a low-tech embedded environment or just to kill the curiosity.

Answer 1

Date.now() wins. See jsperf.com test

But as noted in comments above, the CPU cost is likely uninteresting compared to just about anything else you'll be doing.

@techfoobar mentions the cost of allocating Date objects (or, really, the cost of garbage collecting those Date objects). That may or may not be a significant win, as Date.now() is probably allocating Number objects, which would be about as expensive.

Answer 2

Also, if the timestamp is obtained for anything other than timestamping the data, for example, the timing of code execution, it is always a good idea to think if the same can be achieved via setTimeout or setInterval calls instead, without direct access to timestamp value.