Trying to merge 2 JSON documents using JQ - json

Question

I'm using JQ CLI to merge JSON from document to another. The issue I am facing is that I have select by the value of a property, rather than by a numeric array index
The first file contains a chunk of JSON jqtest.json:
{
"event": [
{
"listen": "test",
"script": {
"exec": [],
"type": "text/javascript"
}
}
]
}
The second file is where I want to merge the JSON into under "accounts" collection.json:
{
"item": [
{
"name": "accounts",
"item": [
{
"name": "Retrieves the collection of Account resources."
}
]
},
{
"name": "accounts mapped",
"item": [
{
"name": "Retrieves the collection of AccountMapped resources."
}
]
}
]
}
What i am trying to do is merge it under "accounts" and under "name": "Retrieves the collection of Account resources." I use the command:
jq -s '
.[0].event += .[1].item |
map(select(.name=="accounts")) |
.[].item
' jqtest.json collection.json
But when executed nothing is outputted. What am doing wrong with JQ or is there another tool i can use to accomplish this?
{
"item": [
{
"name": "accounts",
"item": [
{
"name": "Retrieves the collection of Account resources.",
"event": [
{
"listen": "test",
"script": {
"exec": [],
"type": "text/javascript"
}
}
]
},
{
"name": "accounts mapped",
"item": [
{
"name": "Retrieves the collection of AccountMapped resources."
}
]
}
]
}
]
}

Answer 1

To merge two objects, one can use obj1 + obj2. From this, it follows that obj1 += obj2 can be used to merge an object (obj2) into another existing object (obj1).
Maybe that's what you trying to use. If so, you were missing parens around the expression producing the object to merge into (causing the code to be misparsed), you have the operands to += backwards, you don't actually produce the correct objects on each side of += (or even objects at all), and you didn't narrow down your output (accidentally including jqtest in the output).
Fixed:
jq -s '
( .[1].item[] | select( .name == "accounts" ) | .item[] ) += .[0] | .[1]
' jqtest.json collection.json
Demo on jqplay
I find the following clearer (less mental overhead):
jq -s '
.[0] as $to_insert |
.[1] | ( .item[] | select( .name == "accounts" ) | .item[] ) += $to_insert
' jqtest.json collection.json
Demo
That said, I would avoid slurping in favour of --argfile.
jq --argfile to_insert jqtest.json '
( .item[] | select( .name == "accounts" ) | .item[] ) += $to_insert
' collection.json
Demo on jqplay