Processing string representation of json within jq - json

Question

I have a function in bash psql_json() that hits a postgres database and returns a json. I can not edit this bash function but it injects a postgres statement into this this query which is then sent to the db:
"select row_to_json(t)::json from ($arg) t;"
Where arg is some statement ie:
select * from table
However, this function returns a weirdly formatted json string as seen below:
{\"id\":1,\"firstName\":\"firstName1\",\"lastName\":\"lastName1\"}\n
{\"id\":2,\"firstName\":\"firstName2\",\"lastName\":\"lastName2\"}
The above output is what happens after running these statements:
local_fn="$(mktemp)"
psql_json 'select * from table' > "$local_fn"
cat "$local_fn"
Now when I try to put this json as is into jq, I get the following error:
cat json1.json | jq '.'
jq: error: syntax error, unexpected $end, expecting ';' or ')' (Unix shell quoting issues?)
I found this thread which seems to indicate the issue is that I am passing a string into jq which it doesnt like and is unable to parse, so I tried both:
cat json1.json | jq 'fromjson]'
cat json1.json | jq '[.[]|fromjson]'
and they both return
parse error: Invalid numeric literal at line 1, column 3
Is there any way I can get string representation of the json above into jq in a clean way to process it or would I need to clean/edit the string in bash?

Answer 1

You could fix the input using jq or a text-processing tool such as sed:
< weird.json jq -R 'sub("^";"\"") | sub("$";"\"") | fromjson | fromjson'
or
< weird.json sed -e 's/^/"/' -e 's/$/"/' | jq -R 'fromjson|fromjson'
With your input, the result in both cases is:
{
"id": 1,
"firstName": "firstName1",
"lastName": "lastName1"
}
{
"id": 2,
"firstName": "firstName2",
"lastName": "lastName2"
}