Slack block markdown syntax not working in hashtable

I'm generating a Slack message using a hashtable in Powershell.

Here is how the hashtable is generated:

$serviceitems = foreach ($r in $rows) {
    @{
        type = 'section'
        text = @{
            type = 'mrkdwn'
            text = "*{0}*\n{1:C2}" -f $r[1], $r[0]
        }
    }
    @{
        type = 'divider'
    } 
}

The messsages show up in Slack but the \n prints out instead of going to a new line like it should. The two * make the text bold as intended. I tried adding a backtick to before \n and also tried adding an extra \. Both made no change.

Solution

\ has no special meaning in PowerShell strings.

PowerShell uses ` (the so-called backtick) as the escape character, so you need escape sequence `n inside an expandable (double-quoted) string ("...") in order to embed an actual newline (LF character) in the strings.

Simple example:

PS> "line 1`nline 2" | ForEach-Object { "[$_]" }
[line 1
line 2]

PowerShell happily accepts LF alone as a newline; if you do need CRLF newlines, use `r`n. To refer to the platform-native newline sequence, use [Environment]::NewLine ($([Environment]::NewLine) to use it inside "...").