Merge two complex JSON objects (using jq) - json

Question

I'm trying to replace objects in a complex JSON object. It seemed that the tool jq could be offering the perfect solution, but I'm really struggling with the right choice / chain of filters.
I have a complete configuration JSON object which looks like this (has some more keys in it, shortened it for illustration):
{
"some-array": [
{
"name": "foo",
"attr": "value"
},
{
"name": "foo bar",
"attr": "value"
},
{
"name": "foo bar baz",
"attr": "value"
}
],
"some-other-array": []
}
Now I have another object containing an array with updated objects which I need to merge with the full configuration in some way. I need to find the nested objects by name, add it if it does not exist yet and replace it if it does exist.
{
"some-array": [
{
"name": "foo",
"attr": "new-value",
"new-attrib": "new-value"
},
{
"name": "foo bar",
"attr": "new-value"
}
]
}
So, with the above example, my expected result would be:
{
"some-array": [
{
"name": "foo",
"attr": "new-value",
"new-attrib": "new-value"
},
{
"name": "foo bar",
"attr": "new-value"
},
{
"name": "foo bar baz",
"attr": "value"
}
],
"some-other-array": []
}
I already tried select(."some-array"[].name == "foo") to begin with and a few other things as a jq filter, but I'm struggling to move forward here and would really appreciate some inspiration / an actual solution.
Can anyone tell me if what I'm trying to achieve is actually possible with jq or do I have to find another solution?

Answer 1

Here is a solution to the updated problem. This solution assumes that the names are string-valued. It relies on two helper functions:
# array-to-hash
def a2h(f): reduce .[] as $x ({}; . + {($x | f): $x});
# hash-to-array
def h2a: . as $in | reduce keys_unsorted[] as $k ([]; . + [$in[$k]]);
The first of these creates a "hash" based on an input array, and the second implements the inverse operation.
With these helper functions, the solution can be written:
.["some-array"] |= (a2h(.name) + ($update|.["some-array"] | a2h(.name)) | h2a)
where $update is the "new" value. This solution relies on the "right-dominance" of object-addition.
Output
For the given example, the output is:
{
"some-array": [
{
"name": "foo",
"attr": "new-value",
"new-attrib": "new-value"
},
{
"name": "foo bar",
"attr": "new-value"
},
{
"name": "foo bar baz",
"attr": "value"
}
],
"some-other-array": []
}

Answer 2

Yes, it's possible, and in fact quite easy under various interpretations of the problem as originally stated.
The following solves the the problem as it was originally stated, with "it" being interpreted as .["some-array"] rather than its constituents.
Assuming $update holds the object with the updated information as shown, the update could be performed using this filter:
.["some-array"] = ($update | .["some-array"])
There are many ways to endow $update with the desired value.