Everything you wanted to know about ShouldProcess

Test-ShouldProcess.ps1

# https://learn.microsoft.com/en-us/powershell/scripting/learn/deep-dives/everything-about-shouldprocess
function Test-ShouldProcess {
    [CmdletBinding(
        SupportsShouldProcess,
        ConfirmImpact = 'High'
    )]
    param(
        [Switch]$Force
    )

    if ($Force -and -not $Confirm){
        $ConfirmPreference = 'None'
    }

    echo "`$WhatIfPreference, $WhatIfPreference" # No flag -> False # -Whatif:$false -> False # -Whatif:$true -> True
    echo "`$ConfirmPreference, $ConfirmPreference" # No flag -> High # -Confirm:$false -> None # -Confirm:$true -> Low

    $PSCmdlet.ShouldProcess('TARGET')
    # What if: Performing the operation "FUNCTION_NAME" on target "TARGET".
    
    # Confirm
    # Are you sure you want to perform this action?
    # Performing the operation "Test-ShouldProcess" on target "TARGET".

    $PSCmdlet.ShouldProcess('TARGET','OPERATION')
    # What if: Performing the operation "OPERATION" on target "TARGET".

    # Confirm
    # Are you sure you want to perform this action?
    # Performing the operation "OPERATION" on target "TARGET".

    $PSCmdlet.ShouldProcess('MESSAGE','TARGET','OPERATION')
    # What if: MESSAGE

    # OPERATION
    # TARGET
}


function Test-NestedShouldProcess {
    [CmdletBinding(
        SupportsShouldProcess,
        ConfirmImpact = 'High'
    )]
    param()
    echo "Outer `$WhatIfPreference, $WhatIfPreference" # No flag -> False # -Whatif:$false -> False # -Whatif:$true -> True
    echo "Outer `$ConfirmPreference, $ConfirmPreference" # No flag -> High # -Confirm:$false -> None # -Confirm:$true -> Low
    if ($PSCmdlet.ShouldProcess('This block','Run nested should process')) {
        # WhatIfPreference and ConfirmPreference values are inherited and inner function calls will have these values
        Test-ShouldProcess # No flag prompts # -Confirm:$false doesn't prompt # -Confirm:$true prompts
        Test-ShouldProcess -Confirm:$false # Never prompts
    }
}