Composite Pattern: Simplifies client code by treating individual objects and compositions uniformly, making it easier to work with complex structures

employee.ps1

class Employee {

    $name
    $dept
    $salary
    hidden [Employee[]]$subordinates = @()

    Employee($name, $dept, $salary) {
        $this.name   = $name
        $this.dept   = $dept
        $this.salary = $salary
    }

    Add([Employee]$e) {
        $this.subordinates += $e
    }

    [Employee[]] GetSubordinates() {
        return $this.subordinates
    }

    [string] ToString() {
        return "[{0}] {1}: {2:C0}" -f $this.dept, $this.name, $this.salary
    }
}

Try-CompositePattern.ps1

. .\Employee.ps1

$CEO             = [Employee]::new("John","CEO", 30000)
$HeadSales       = [Employee]::new("Robert","Head Sales", 20000)
$HeadMarketing   = [Employee]::new("Michel","Head Marketing", 20000)
$clerk1          = [Employee]::new("Laura","Marketing", 10000)
$clerk2          = [Employee]::new("Bob","Marketing", 10000)
$salesExecutive1 = [Employee]::new("Richard","Sales", 10000)
$salesExecutive2 = [Employee]::new("Rob","Sales", 10000)

$CEO.Add($HeadSales)
$CEO.Add($HeadMarketing)

$HeadSales.Add($salesExecutive1)
$HeadSales.Add($salesExecutive2)

$HeadMarketing.Add($clerk1)
$HeadMarketing.Add($clerk2)

"$CEO"
foreach($headEmployee in $CEO.GetSubordinates()) {
    "`t$headEmployee"

    foreach ($employee in $headEmployee.GetSubordinates()) {
        "`t`t$employee"
    }
}

[CEO] John: $30,000
        [Head Sales] Robert: $20,000
                [Sales] Richard: $10,000
                [Sales] Rob: $10,000
        [Head Marketing] Michel: $20,000
                [Marketing] Laura: $10,000
                [Marketing] Bob: $10,000