append json array using jq [duplicate]

Question

I have a json file which I am fetching from consul and the results are very simple:

[ { "name" : Jon", "class" : "senior" } ]

I want to update the array with below json:

{ "name" : santa", "class" : "christmas" }

and the output should be:

[ { "name" : Jon", "class" : "senior" }, { "name" : santa", "class" : "christmas" } ]

This looks very simple but I am unable to do it till now.

this is what I have been trying with jq:

JSON=[{ "name" : Jon", "class" : "senior" }]

echo $JSON | jq '.[] += { "new_key" : "new_value" }'

I followed some answers on stackoverflow but most of them are about adding a single element.

if you have input [ { "name": "Jon", "class": "senior" } ] { "name": "santa", "class": "christmas" } then filter input as $first | $first+[input] should work. jqplay.org/s/YsSEXxiWbQ — Logan Lee
– Logan Lee, Commented May 3, 2022 at 1:09

pmf · Accepted Answer · 2021-12-15 10:22:49Z

4

There are several issues with your script. Generally, this should work (but still needs improvement on certain levels):

JSON='[{"name": "Jon", "class": "senior"}]'
echo "$JSON" | jq '. += [{"new_key": "new_value"}]'

[
  {
    "name": "Jon",
    "class": "senior"
  },
  {
    "new_key": "new_value"
  }
]

answered Dec 15, 2021 at 10:22

pmf

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Comments

Léa Gris · Accepted Answer · 2021-12-15 11:42:21Z

2

Anyway as a shortcut, here is how you do it without piping the source JSON array:

JSON='[{"name": "Jon", "class": "senior"}]'
jq --null-input --argjson  a "$JSON" '$a  + [{"name" : "santa", "class" : "christmas" }]'

answered Dec 15, 2021 at 11:42

Léa Gris

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