Transpose JSON array index column values into rows & export to CSV - arrays

Question

I have a JSON file with below format:
[
{
"id": "12345",
"name": "test_group",
"members":
[
{
"id": "11111",
"name": "test_member_1"
},
{
"id": "22222",
"name": "test_member_2"
},
{
"id": "33333",
"name": "test_member_3"
}
]
}
]
My requirement is to convert these into below format/output to CSV:
groupId,groupName,memberId,memberName
12345,test_group,11111,test_member_1
12345,test_group,22222,test_member_2
12345,test_group,33333,test_member_3
I am able to get the array index values as concatenated strings in one column using below code, but need the output in above format only:
$jsonfile = 'C:\newjsonfile.json'
$outputcsv = 'C:\newcsvfile.csv'
$fields=#(
#{Name='groupId';Expression={$_.id}}
,#{Name='groupName';Expression={$_.name}}
,#{Name='memberId';Expression={$_.members.id, -join '|~|'}}
,#{Name='memberName';Expression={$_.members.name -join '|~|'}}
)
(Get-Content $jsonfile -Raw | ConvertFrom-Json) |
Select-Object -Property $fields |
Export-Csv $outputcsv -NoTypeInformation -Force
CSV Output from above query:
groupId, groupName, memberId, memberName
----- --------- -------- ----------
12345, test_group, {11111 |~| 22222 |~| 33333}, {test_member_1 |~| test_member_2 |~| test_member_3}
Please help/suggest in resolving this query in PowerShell.
Current version is:
PS C:\WINDOWS\system32> $PSVersionTable.PSVersion
Major Minor Build Revision
----- ----- ----- --------
5 1 17134 407

Answer 1

You want to combine information from a parent object with information from nested child objects. To do that you need to store the information from the parent in variables and then inject it when processing the child objects:
(Get-Content $jsonfile -Raw | ConvertFrom-Json) | ForEach-Object {
$gid = $_.id
$name = $_.name
$_.members |
Select-Object #{n='groupId';e={$gid}},
#{n='groupName';e={$name}},
#{n='memberId';e={$_.id}},
#{n='memberName';e={$_.name}}
} | Export-Csv $outputcsv -NoType -Force