Run results for: new Date(date) vs new Date(normalizeToLocalDate(date)) 2

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser: Chrome 127

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

new Date(dateOnlyISO)

5.8M/s

new Date(dateTimeISO)

4.3M/s

new Date(normalizeToLocalDate(dateTimeISO))

4.3M/s

new Date(normalizeToLocalDate(dateOnlyISO))

3.0M/s

View exact numbers

Test name	Executions per second
✓ new Date(dateOnlyISO)	5,783,702 Ops/sec
new Date(dateTimeISO)	4,279,278 Ops/sec
new Date(normalizeToLocalDate(dateTimeISO))	4,273,234 Ops/sec
new Date(normalizeToLocalDate(dateOnlyISO))	2,984,260 Ops/sec

Script Preparation code:

var dateTimeISO = '2024-08-21T17:00:00.000Z'
var dateOnlyISO = '2024-08-21'

var normalizeToLocalDate = (date) => ` ${date}`

Tests:

new Date(dateTimeISO)
new Date(dateTimeISO)
new Date(normalizeToLocalDate(dateTimeISO))
new Date(normalizeToLocalDate(dateTimeISO))
new Date(dateOnlyISO)
new Date(dateOnlyISO)
new Date(normalizeToLocalDate(dateOnlyISO))
new Date(normalizeToLocalDate(dateOnlyISO))