Public/Get-ChildPage.ps1

function Get-ChildPage {
    [CmdletBinding( SupportsPaging = $true )]
    [OutputType([ConfluencePS.Page])]
    param (
        [Parameter( Mandatory = $true )]
        [URi]$apiURi,

        [Parameter( Mandatory = $true )]
        [PSCredential]$Credential,

        [Parameter(
            Position = 0,
            Mandatory = $true,
            ValueFromPipeline = $true,
            ValueFromPipelineByPropertyName = $true
        )]
        [ValidateRange(1, [int]::MaxValue)]
        [Alias('ID')]
        [int]$PageID,

        [switch]$Recurse,

        [ValidateRange(1, [int]::MaxValue)]
        [int]$PageSize = 25
    )

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

        $depthLevel = "child"
    }

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

        if (($_) -and -not($_ -is [ConfluencePS.Page] -or $_ -is [int])) {
            $message = "The Object in the pipe is not a Page."
            $exception = New-Object -TypeName System.ArgumentException -ArgumentList $message
            Throw $exception
        }

        if ($PsCmdlet.ParameterSetName -eq "byObject") {
            $PageID = $InputObject.ID
        }
        if ($Recurse) { $depthLevel = "descendant" } # depth = ALL

        $iwParameters = @{
            Uri           = "$apiURi/content/{0}/{1}/page" -f $PageID, $depthLevel
            Method        = 'Get'
            GetParameters = @{
                expand = "space,version,body.storage,ancestors"
                limit  = $PageSize
            }
            OutputType    = [ConfluencePS.Page]
            Credential    = $Credential
        }

        # Paging
        ($PSCmdlet.PagingParameters | Get-Member -MemberType Property).Name | ForEach-Object {
            $iwParameters[$_] = $PSCmdlet.PagingParameters.$_
        }

        Invoke-Method @iwParameters
    }

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