The first number, HrTime[0], is UNIX Epoch time in seconds since 00:00:00 UTC on 1 January 1970.
The second number, HrTime[1], represents the partial second elapsed since Unix Epoch time represented by first number in nanoseconds.
For example, 2021-01-01T12:30:10.150Z in UNIX Epoch time in milliseconds is represented as 1609504210150.
The first number is calculated by converting and truncating the Epoch time in milliseconds to seconds:
HrTime[0] = Math.trunc(1609504210150 / 1000) = 1609504210.
The second number is calculated by converting the digits after the decimal point of the subtraction, (1609504210150 / 1000) - HrTime[0], to nanoseconds:
HrTime[1] = Number((1609504210.150 - HrTime[0]).toFixed(9)) * 1e9 = 150000000.
This is represented in HrTime format as [1609504210, 150000000].
Defines High-Resolution Time.
The first number, HrTime[0], is UNIX Epoch time in seconds since 00:00:00 UTC on 1 January 1970. The second number, HrTime[1], represents the partial second elapsed since Unix Epoch time represented by first number in nanoseconds. For example, 2021-01-01T12:30:10.150Z in UNIX Epoch time in milliseconds is represented as 1609504210150. The first number is calculated by converting and truncating the Epoch time in milliseconds to seconds: HrTime[0] = Math.trunc(1609504210150 / 1000) = 1609504210. The second number is calculated by converting the digits after the decimal point of the subtraction, (1609504210150 / 1000) - HrTime[0], to nanoseconds: HrTime[1] = Number((1609504210.150 - HrTime[0]).toFixed(9)) * 1e9 = 150000000. This is represented in HrTime format as [1609504210, 150000000].