JQ if else then NULL Return - arrays

Question

I'm trying to filter and output from JSON with jq.
The API will sometime return an object and sometime an array, I want to catch the result using an if statement and return empty string when the object/array is not available.
{
"result":
{
"entry": {
"id": "207579",
"title": "Realtek Bluetooth Mesh SDK on Linux\/Android Segmented Packet reference buffer overflow",
"summary": "A vulnerability, which was classified as critical, was found in Realtek Bluetooth Mesh SDK on Linux\/Android (the affected version unknown). This affects an unknown functionality of the component Segmented Packet Handler. There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.",
"details": {
"affected": "A vulnerability, which was classified as critical, was found in Realtek Bluetooth Mesh SDK on Linux\/Android (the affected version unknown).",
"vulnerability": "The manipulation of the argument reference with an unknown input leads to a unknown weakness. CWE is classifying the issue as CWE-120. The program copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.",
"impact": "This is going to have an impact on confidentiality, integrity, and availability.",
"countermeasure": "There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product."
},
"timestamp": {
"create": "1661860801",
"change": "1661861110"
},
"changelog": [
"software_argument"
]
},
"software": {
"vendor": "Realtek",
"name": "Bluetooth Mesh SDK",
"platform": [
"Linux",
"Android"
],
"component": "Segmented Packet Handler",
"argument": "reference",
"cpe": [
"cpe:\/a:realtek:bluetooth_mesh_sdk"
],
"cpe23": [
"cpe:2.3:a:realtek:bluetooth_mesh_sdk:*:*:*:*:*:*:*:*"
]
}
}
}
Would also like to to use the statement globally for the whole array output so I can parse it to .csv and escape the null, since sofware name , can also contain an array or an object. Having a global if statement with simplify the syntax result and suppress the error with ?
The error i received from bash
jq -r '.result [] | [ "https://vuldb.com/?id." + .entry.id ,.software.vendor // "empty",(.software.name | if type!="array" then [.] | join (",") else . //"empty" end )?,.software.type // "empty",(.software.platform | if type!="array" then [] else . | join (",") //"empty" end )?] | #csv' > tst.csv
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 7452 0 7393 100 59 4892 39 0:00:01 0:00:01 --:--:-- 4935
jq: error (at <stdin>:182): Cannot iterate over null (null)
What I have tried is the following code which i tried to demo https://jqplay.org/ which is incorrect syntax
.result [] |( if .[] == null then // "empty" else . end
| ,software.name // "empty" ,.software.platform |if type!="array" then [.] // "empty" else . | join (",") end)
Current output
[
[
"Bluetooth Mesh SDK"
],
"Linux,Android"
]
Desired outcome
[
"Bluetooth Mesh SDK",
"empty"
]

Answer 1

After fixing your input JSON, I think you can get the desired output by using the following JQ filter:
if (.result | type) == "array" then . else (.result |= [.]) end \
| .result[].software | [ .name, (.platform // [ "Empty" ] | join(",")) ]
Where
if (.result | type) == "array" then . else (.result |= [.]) end
Wraps .result in an array if type isn't array
.result[].software
Loops though the software in each .result obj
[ .name, (.platform // [ "Empty" ] | join(",")) ]
Create an array with .name and .platform (which is replaced by [ "Empty" ] when it doesn't exist. Then it's join()'d to a string
Outcome:
[
"Bluetooth Mesh SDK",
"Linux,Android"
]
Online demo
Or
[
"Bluetooth Mesh SDK",
"Empty
]
Online demo