Simple csvtojson script with jq

csvtojson.jq

#!/usr/bin/env -S jq -Rnf

def csvarray:split(",")|map(fromjson);
def objectify($ks): [$ks,(.|csvarray)]|[transpose[] as [$key,$value]|{$key,$value}]|from_entries;

(input|csvarray) as $keys|[inputs|objectify($keys)|.csv_filename=input_filename]
| reduce .[] as $o ({}; .[$o.csv_filename]+=[($o|del(.csv_filename))])
| if length == 1 and has("<stdin>") then ."<stdin>" else . end