PowerShell ConvertTo-PascalCase, ConvertTo-SnakeCase

PascalSnakeCase.ps1

function ConvertTo-PascalCase
{
    [OutputType('System.String')]
    param(
        [Parameter(Position=0)]
        [string] $Value
    )

    # https://devblogs.microsoft.com/oldnewthing/20190909-00/?p=102844
    return [regex]::replace($Value.ToLower(), '(^|_)(.)', { $args[0].Groups[2].Value.ToUpper()})
}

function ConvertTo-SnakeCase
{
    [OutputType('System.String')]
    param(
        [Parameter(Position=0)]
        [string] $Value
    )

    return [regex]::replace($Value, '(?<=.)(?=[A-Z])', '_').ToLower()
}