--export-json option does not follow --time-unit millisecond

[LakshyAAAgrawal]

When I run hyperfine as follows:

hyperfine --export-json export_file.json --time-unit millisecond ...

The information printed on screen contains the runtime in ms, but the values in json are in seconds.

STDOUT:

Benchmark 1:
  Time (mean ± σ):     24338.2 ms ± 586.0 ms    [User: 33456.5 ms, System: 810.7 ms]
  Range (min … max):   23236.7 ms … 24935.3 ms    10 runs

Benchmark 2:
  Time (mean ± σ):     30608.8 ms ± 1589.9 ms    [User: 30179.0 ms, System: 370.1 ms]
  Range (min … max):   28544.2 ms … 33266.7 ms    10 runs

Benchmark 3:
  Time (mean ± σ):     2440.0 ms ± 110.5 ms    [User: 7190.9 ms, System: 510.5 ms]
  Range (min … max):   2320.6 ms … 2687.1 ms    10 runs

Benchmark 4: 
  Time (mean ± σ):     271.3 ms ±   9.7 ms    [User: 277.8 ms, System: 43.0 ms]
  Range (min … max):   261.7 ms … 287.7 ms    11 runs

JSON:

{
  "results": [
    {
      "command": "",
      "mean": 24.33821241768,
      "stddev": 0.5860376164918488,
      "median": 24.519336471680003,
      "user": 33.45652016,
      "system": 0.8106670799999998,
      "min": 23.236672976180003,
      "max": 24.935324420180002,
      "times": [
        24.377126650180003,
        24.935324420180002,
        23.673355310180003,
        24.860536787180003,
        24.71504739118,
        24.013392875180003,
        23.236672976180003,
        24.661546293180002,
        24.91582306918,
        23.993298404180003
      ],
      "exit_codes": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ],
      "parameters": {
        ...
      }
    },
    {
      "command": "",
      "mean": 30.608782593479997,
      "stddev": 1.589898056911429,
      "median": 30.16905129018,
      "user": 30.17903756,
      "system": 0.37007848,
      "min": 28.544227869180002,
      "max": 33.26665792318,
      "times": [
        29.665700734180003,
        29.242187895180002,
        28.544227869180002,
        29.26461614718,
        33.26665792318,
        31.94330033318,
        29.61887199018,
        30.67240184618,
        31.397677382180003,
        32.47218381418
      ],
      "exit_codes": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ],
      "parameters": {
        ...
      }
    },
    {
      "command": "",
      "mean": 2.44003735098,
      "stddev": 0.11049737756969906,
      "median": 2.40457368518,
      "user": 7.1908692599999995,
      "system": 0.51047328,
      "min": 2.32056399918,
      "max": 2.6871016281799998,
      "times": [
        2.6871016281799998,
        2.50202483118,
        2.37684932518,
        2.53409697118,
        2.3867186171799997,
        2.45987207818,
        2.35651591618,
        2.35420139018,
        2.32056399918,
        2.4224287531799997
      ],
      "exit_codes": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ],
      "parameters": {
        ...
      }
    },
    {
      "command": "..",
      "mean": 0.2713198007254546,
      "stddev": 0.009676558478438305,
      "median": 0.26807056817999997,
      "user": 0.2778479418181818,
      "system": 0.043043134545454546,
      "min": 0.26173708417999997,
      "max": 0.28768982918,
      "times": [
        0.26173708417999997,
        0.27555605518,
        0.28768982918,
        0.27888181118,
        0.28593935018,
        0.26807056817999997,
        0.26298405418,
        0.26192160718,
        0.27402342418,
        0.26329744018,
        0.26441658417999997
      ],
      "exit_codes": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ],
      "parameters": {
           ...
      }
    }
  ]
}

[sharkdp]

The information printed on screen contains the runtime in ms, but the values in json are in seconds.

Yes, that is expected. We want the JSON format to be a format for interchange between hyperfine and other tools. We therefore fix the times to be in seconds.

--time-unit only influences what is being displayed on the console... and other (markup) export formats.

This should probably be clarified in the documentation.