PowerShell Function IsNullOrEmpty

Function IsNullOrEmpty {
<#
.SYNOPSIS
    Determine if an object is $null or empty.
.DESCRIPTION
    Determine if an object is $null or empty.
.INPUT
    Accepts pipeline input of any object type.
.OUTPUTS
    system.boolean
.PARAMETER InputObject
    Input object to examine for $null or empty value.
.EXAMPLE
    IsNullOrEmpty($null)
.EXAMPLE
    An example showing use with the pipeline:
    @(1,'',2,'String',$null,@(),@(3,4,5)) | Where-Object { -not (IsNullOrEmpty($_)) } | Write-Host
    Only writes array elements to the console if they are not $null or empty.
.NOTES
    Please note that strongly typed variables cannot be set to $null in PowerShell.

    If you set  [int32]$a  = $null    ==> PowerShell will set $a = 0
    If you set  [switch]$b = $null    ==> PowerShell will set $b = $false
    If you set  [string]$c = $null    ==> PowerShell will set $c = ''

    After people complained about not being able to set variables of [string] type to $null,
     PowerShell 3 gained the ability to set a [string] type to $null like this:
     [string]$d = [System.Management.Automation.Language.NullString]::Value
.LINK
#>
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)]
        [AllowNull()]
        [AllowEmptyString()]
        [AllowEmptyCollection()]
        $InputObject
    )
    Process {
        ## Switching the comparison order of this 'If' statement can give inaccurate
        ## results when arrays are involved, so don't touch.
        If ($null -eq $InputObject) {
            Write-Output $true
        }
        ElseIf (($InputObject -is [array]) -and (-not $InputObject.Count)) {
            Write-Output $true
        }
        ElseIf (($InputObject -is [string]) -and (-not $InputObject)) {
            Write-Output $true
        }
        ## To handle null values from SQL databases.
        ElseIf ($InputObject -is [DBNull]) {
            Write-Output $true
        }
        Else {
            Write-Output $false
        }
    }
}