Public/Get-JiraIssueComment.ps1

function Get-JiraIssueComment {
    [CmdletBinding()]
    param(
        [Parameter( Mandatory, ValueFromPipeline, ValueFromPipelineByPropertyName )]
        [ValidateNotNullOrEmpty()]
        [ValidateScript(
            {
                if (("JiraPS.Issue" -notin $_.PSObject.TypeNames) -and (($_ -isnot [String]))) {
                    $errorItem = [System.Management.Automation.ErrorRecord]::new(
                        ([System.ArgumentException]"Invalid Type for Parameter"),
                        'ParameterType.NotJiraIssue',
                        [System.Management.Automation.ErrorCategory]::InvalidArgument,
                        $_
                    )
                    $errorItem.ErrorDetails = "Wrong object type provided for Issue. Expected [JiraPS.Issue] or [String], but was $($_.GetType().Name)"
                    $PSCmdlet.ThrowTerminatingError($errorItem)
                    <#
                      #ToDo:CustomClass
                      Once we have custom classes, this check can be done with Type declaration
                    #>

                }
                else {
                    return $true
                }
            }
        )]
        [Alias('Key')]
        [Object]
        $Issue,

        [PSCredential]
        $Credential
    )

    begin {
        Write-Verbose "[$($MyInvocation.MyCommand.Name)] Function started"
    }

    process {
        Write-DebugMessage "[$($MyInvocation.MyCommand.Name)] ParameterSetName: $($PsCmdlet.ParameterSetName)"
        Write-DebugMessage "[$($MyInvocation.MyCommand.Name)] PSBoundParameters: $($PSBoundParameters | Out-String)"

        # Find the proper object for the Issue
        $issueObj = Resolve-JiraIssueObject -InputObject $Issue -Credential $Credential

        $parameter = @{
            URI        = "{0}/comment" -f $issueObj.RestURL
            Method     = "GET"
            Credential = $Credential
        }
        Write-Debug "[$($MyInvocation.MyCommand.Name)] Invoking JiraMethod with `$parameter"
        $result = Invoke-JiraMethod @parameter

        Write-Output (ConvertTo-JiraComment -InputObject $result.comments)
    }

    end {
        Write-Verbose "[$($MyInvocation.MyCommand.Name)] Complete"
    }
}