Accept a list of (object) lists

[iRon7]

See: PowerShell/PowerShell#20126

For objects like: $a = '[[1, 2], [3, 4],[5,6]]' | ConvertFrom-Json
Instead of:

$a = '[[1, 2], [3, 4],[5,6]]' | ConvertFrom-Json
$a[0] | Join $a[1] | Join $a[2] | ForEach-Object { $_ -Join ' : ' }

I would like to iterate through all embedded lists, wishful thinking:

$a = '[[1, 2], [3, 4],[5,6]]' | ConvertFrom-Json
$a | Join -EachList | ForEach-Object { $_ -Join ' : ' }

[iRon7]

Complex due to several Pipeline dependencies and exceptions