Why is Date comparison so much slower than comparing against the result of getTime?

[Matthew Caruana Galizia]

One of my colleagues wrote a test that shows that comparing two Date objects is ~95% slower than comparing against the result of getTime. Why is this so?

[Florian Schneider]

This is expected: When comparing two objects like Date with <, they are converted into primitive values (numbers) first. This ToPrimitive-conversion takes most of the time when comparing two Date objects. Comparing the result of getTime() on the other hand is just a comparison of two numbers which is way more efficient.

2012/10/5 Matthew Caruana Galizia <mat...@gmail.com>

One of my colleagues wrote a test that shows that comparing two Date objects is ~95% slower than comparing against the result of getTime. Why is this so?

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[Matthew Caruana Galizia]

Thanks, that bit makes sense. Though doesn't getTime() produce a number and if so what's the difference between an explicit and implicit conversion to a primitive value?