Group arrays and move them under new object when array names are not known

Question

I have the following JSON

[
    {
        "name": "T1",
        "R10": ["A","B"]
    },
    {
        "name": "T1",
        "M20": ["C"]
    },
    {
        "name": "A1",
        "C20": ["A","B"]
    },
    {
        "name": "B1",
        "V30": ["3"]
    },
    {
        "name": "C1",
        "X50": ["1"]
    }
]

I want to group arrays based on "name" and push them under new "Arrays" object. So the result should look like the following:

[
    {
        "name": "T1",
        "Arrays": {
            "R10": ["A","B"],
            "M20": ["C"]
        }
    },
    {
        "name": "A1",
        "Arrays": {
            "C20": ["A","B"]
        }
    },
    {
        "name": "B1",
        "Arrays": {
            "V30": ["3"]
        }
    },
    {
        "name": "C1",
        "Arrays": {
            "X50": ["1"]
        }
    }
]

I can do a selection based on the value of "name" [.[] | select ( .name | test("T1") )] | add - it does group arrays together, But I can't figure out how to generalize the filter - to apply it to the whole JSON instead of filtering based on the name.

I am also stuck on how to push arrays under the "Arrays" object if I do not know the names of the arrays in advance.

Answer 1

This would definitely need group_by/1 on the .name field and later reorder the objects as desired.

[ group_by(.name)[] | add ] | map( { name: .name, Arrays: del(.name) } )

Since the group-by functions do an internal sort on the fields applied, i.e. .name in your case, the key ordering of the final result is determined by the ascending order of .name field.

^{Demo - jqplay}