log.ps1

function Test-Command
{
[cmdletbinding()]
Param()
    write-verbose -Message "Start"    
}

function Write-Verbose
{
[cmdletbinding()]
Param(
    [string]
    $Message
)
    $date = [datetime]::Now
    
    $parentFunction = (Get-Variable -Name MyInvocation -Scope 1).Value.MyCommand.Name

    $logFile = $env:SystemDrive | 
        Join-Path -ChildPath temp |
        Join-Path -ChildPath log.txt

    $objectLogFile = $env:SystemDrive | 
        Join-Path -ChildPath temp |
        Join-Path -ChildPath log.json
    
    $logThis = "$date - $message"
    
    $logObj = [pscustomobject][ordered]@{
        Date = $date
        Command = $parentFunction
        Message = $Message
    }

    Add-Content -Path $logFile -Value $logThis -Encoding UTF8
    $logObj | ConvertTo-Json -Compress | Add-Content -Path $objectLogFile -Encoding UTF8

    Microsoft.PowerShell.Utility\Write-Verbose -Message "$parentFunction - $Message"
}