Get-CommandChoice.ps1

function Get-CommandChoice
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory=$true)]
        [Array]$Array,
        
        [Parameter(Mandatory=$true)]
        [string]$caption,
        
        [Parameter(Mandatory=$true)]
        [string]$Message,
        
        [int]$DefaultChoice = 0
    )
    
    $Choices = [System.Management.Automation.Host.ChoiceDescription[]] @($Array)
    $Choice = $host.ui.PromptForChoice($Caption,$Message, $Choices,$DefaultChoice)
    
    Return $Array[$Choice]
}

function Invoke-TestCommand {
    $Extensions = Get-Childitem -path "$Env:USERPROFILE\.vscode-insiders\extensions\gerane*" -Directory
    $Caption = "Please select a an Extension"
    $Message = "Package.json will be launched"
    
    $CommandChoice = Get-CommandChoice -Array $Extensions.Name -caption $Caption -Message $Message
    
    $Package = "$Env:USERPROFILE\.vscode-insiders\extensions\$CommandChoice\package.json"
    $psEditor.Workspace.OpenFile($Package)
}

Register-EditorCommand `
    -Name "MyModule.OpenExtPackageJson" `
    -DisplayName "Open Extension Package.json" `
    -Function Invoke-TestCommand