Test-InvokeCommand.ps1

function Invoke-TestCommand {
    $Extensions = Get-Childitem -path "$Env:USERPROFILE\.vscode-insiders\extensions\gerane*" -Directory

    $caption = "Please select a an Extension"
    $message = "Package.json will be launched"
    [int]$defaultChoice = 0
    $Choices = [System.Management.Automation.Host.ChoiceDescription[]] @($Extensions.Name)
    
    $TestParam = $host.ui.PromptForChoice($caption,$message, $choices,$defaultChoice)
    $ExtDir = $Extensions[$TestParam].FullName
    $Package = Get-ChildItem -path "$ExtDir\package.json"
    $psEditor.Workspace.OpenFile($Package)
}

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