ConvertTo-Json using Nan and Infinity Comparison

Json With Nan Comparison.md

About

Compare if NaN fails a round trip in Powershell or when using System.Text.Json

Ran using: pwsh.exe 7.4. context

Tests

$infinity = 0.3 / 0.0 
$nan = 0.0 / $Null

$doc = @{ 
    Inf = $infinity
    Nan = $nan
}
$infinity -is [double] # true
$Nan -is [double]      # true

This 'works' as in there are no errors. Round-trip fails because they import as text.

ConvertTo-Json -InputObject $doc -Compress
# out: {"Inf":"Infinity","Nan":"NaN"}

try Serialize<Double>()

[System.Text.Json.JsonSerializer]::Serialize[double]( $infinity )
[System.Text.Json.JsonSerializer]::Serialize[double]( $nan )

Both throw the same error

 Exception calling "Serialize" with "1" argument(s): ".NET number values such as positive and negative infinity cannot
 be written as valid JSON. To make it work when using 'JsonSerializer', consider specifying 
 'JsonNumberHandling.AllowNamedFloatingPointLiterals' (see https://docs.microsoft.com/dotnet/api/system.text.json.serialization.jsonnumberhandling)."

[System.Text.Json.JsonSerializer]::Serialize[double]( 
    $nan, 
    [System.Text.Json.JsonSerializerOptions]@{ NumberHandling = 'AllowNamedFloatingPointLiterals' } )
# Out:
"NaN"

[System.Text.Json.JsonSerializer]::Serialize[double]( $infinity, [System.Text.Json.JsonSerializerOptions]@{ NumberHandling = 'AllowNamedFloatingPointLiterals' } )

# Out:
"Infinity"

Deserialize<T>() and Deserialize()

[System.Text.Json.JsonSerializer]::Deserialize[double]( '0.3', [System.Text.Json.JsonSerializerOptions]@{ NumberHandling = 'AllowNamedFloatingPointLiterals' } )
# out
0.3

[System.Text.Json.JsonSerializer]::Deserialize[double[]]( 
    '[ 0.3, 4.3 ]',
    [System.Text.Json.JsonSerializerOptions]@{ NumberHandling = 'AllowNamedFloatingPointLiterals' } )
    
# out:
0.3, 4.3
    

[System.Text.Json.JsonSerializer]::Deserialize[double]( $nan, [System.Text.Json.JsonSerializerOptions]@{ NumberHandling = 'AllowNamedFloatingPointLiterals' } )

# out:
Exception calling "Deserialize" with "2" argument(s): "'N' is an invalid start of a value. 
    Path: $ | LineNumber: 0 | BytePositionInLine: 0."