Document the HrTime format

[qaas]

• This only affects the JavaScript OpenTelemetry library
• This may affect other libraries, but I would like to get opinions here first

Hi,

I am implementing openteletry for both python and JS. I would like that the docs are expanded on the HrTime format. For example:

export declare type HrTime = [number, number];

What do the first and the 2nd element of the list represent? I can deduct that the first will be Unix epoch time, but what would the 2nd one be representing?

Thank you!

[dyladan]

Sorry for this oversight on the docs. I'll make sure it gets corrected.

You are correct that the first number is unix epoch seconds. The second number represents the partial second elapsed since that second in nanoseconds.

For example, the date new Date('2021-12-01T15:40:20.050Z') is represented in unix ms as 1638373220050. This is 163837322 seconds and 050 ms. It would be represented in HrTime format as [1638373220, 50000000] which corresponds to 1638373220 seconds and 50000000 nanoseconds since the epoch.

The reason to use this format instead of the simpler ms since epoch format is to get extremely high resolution times for very short spans.

[qaas]

Thank you Daniel for your quick reply!
I thought the 2nd param will be time-related too :) but nanoseconds are like quantum physics time resolution :)

Do you want me to close this, as your reply is more than sufficient?

Best regards,
Dragos

[dyladan]

No it should be documented so others don't have the same question in the future.

[JamesJHPark]

Hi, I would like to work on this issue. Can you please assign me this issue?