Pipe complete array-objects instead of array items one at a time?

Question

How do you send the output from one CmdLet to the next one in a pipeline as a complete array-object instead of the individual items in the array one at a time?

Answer 1

There's an old-school solution, if you don't mind that your process is a function.

Example: You want an array copied to the clipboard in a way that allows you to build it again on another system without any PSRemoting connectivity. So you want an array containing "A", "B", and "C" to transmute to a string: @("A","B","C") ...instead of a literal array.

So you build this (which isn't optimal for other reasons, but stay on topic):

# Serialize-List

param 
(
    [Parameter(Mandatory, ValueFromPipeline)]
    [string[]]$list
)
    $output = "@(";

    foreach ($element in $list)
    {
        $output += "`"$element`","
    }

    $output = $output.Substring(0, $output.Length - 1)
    $output += ")"
    $output

and it works when you specify the array as a parameter directly:

Serialize-List $list

@("A","B","C")

...but not so much when you pass it through the pipeline:

$list | Serialize-List

@("C")

But refactor your function with begin, process, and end blocks:

# Serialize-List

param 
(
    [Parameter(Mandatory, ValueFromPipeline)]
    [string[]]$list
)

begin
{
    $output = "@(";
}

process
{
    foreach ($element in $list)
    {
        $output += "`"$element`","
    }
}

end
{
    $output = $output.Substring(0, $output.Length - 1)
    $output += ")"
    $output
}

...and you get the desired output both ways.

Serialize-List $list

@("A","B","C")

$list | Serialize-List

@("A","B","C")