PowerShell implementing -AsJob for a cmdlet - powershell

Question

Is there a nice way to implement the switch parameter -AsJob in custom cmdlets, like Invoke-Command has?
The only way I thought about this is:
function Use-AsJob {
[CmdletBinding()]
[OutputType()]
param (
[Parameter(Mandatory = $true)]
[string]
$Message,
[switch]
$AsJob
)
# Wrap Script block in a variable
$myScriptBlock = {
# stuff
}
if ($AsJob) {
Invoke-Command -ScriptBlock $myScriptBlock -AsJob
}
else {
Invoke-Command -ScriptBlock $myScriptBlock
}
}
Is there a better approach? I couldn't find Microsoft docs on this, any lead helps.

Answer 1

If we make the following assumptions:
Command is a script function
Function does not rely on module state
Then you can use the following boilerplate for any command:
function Test-AsJob {
param(
[string]$Parameter = '123',
[switch]$AsJob
)
if ($AsJob) {
# Remove the `-AsJob` parameter, leave everything else as is
[void]$PSBoundParameters.Remove('AsJob')
# Start new job that executes a copy of this function against the remaining parameter args
return Start-Job -ScriptBlock {
param(
[string]$myFunction,
[System.Collections.IDictionary]$argTable
)
$cmd = [scriptblock]::Create($myFunction)
& $cmd #argTable
} -ArgumentList $MyInvocation.MyCommand.Definition,$PSBoundParameters
}
# here is where we execute the actual function
return "Parameter was '$Parameter'"
}
Now you can do either:
PS C:\> Test-AsJob
Parameter was '123'
PS C:\> Test-AsJob -AsJob |Receive-Job -Wait
Parameter was '123'