how to insert json var into another json array in bash - json

Question

Could you please assist me to on how I can merge two json variables in bash to get the desired output mentioned below {without manually lopping over .data[] array} ? I tired echo "${firstJsonoObj} ${SecondJsonoObj}" | jq -s add but it didn't parse through the array.
firstJsonoObj='{"data" :[{"id": "123"},{"id": "124"}]}'
SecondJsonoObj='{"etag" :" 234324"}'
desired output
{"data" :[{"id": "123", "etag" :" 234324"},{"id": "124", "etag" :" 234324"}]}
Thanks in advance!

Answer 1

You can append to each data element using +=:
#!/bin/bash
firstJsonoObj='{"data" :[{"id": "123"},{"id": "124"}]}'
SecondJsonoObj='{"etag" :" 234324"}'
jq -c ".data[] += $SecondJsonoObj" <<< "$firstJsonoObj"
Output:
{"data":[{"id":"123","etag":" 234324"},{"id":"124","etag":" 234324"}]}

Answer 2

Please don't use double quotes to inject data from shell into code. jq provides the --arg and --argjson options to do that safely:
#!/bin/bash
firstJsonoObj='{"data" :[{"id": "123"},{"id": "124"}]}'
SecondJsonoObj='{"etag" :" 234324"}'
jq --argjson x "$SecondJsonoObj" '.data[] += $x' <<< "$firstJsonoObj"
# or
jq --argjson a "$firstJsonoObj" --argjson b "$SecondJsonoObj" -n '$a | .data[] += $b'
{
"data": [
{
"id": "123",
"etag": " 234324"
},
{
"id": "124",
"etag": " 234324"
}
]
}

Answer 3

jq -s add will not work because you want to add the second document to a deeper level within the first. Use .data[] += input (without -s), with . acessing the first and ìnput accessing the second input:
echo "${firstJsonoObj} ${SecondJsonoObj}" | jq '.data[] += input'
Or, as bash is tagged, use a Heredoc:
jq '.data[] += input' <<< "${firstJsonoObj} ${SecondJsonoObj}"
Output:
{
"data": [
{
"id": "123",
"etag": " 234324"
},
{
"id": "124",
"etag": " 234324"
}
]
}
Demo