Docs: sort_by() doesn't mention sorting by multiple keys of an object

[jbrains]

I wanted to sort an array of objects by multiple keys (to break ties in the first key). The Manual doesn't describe this at all, but a Stack Overflow article showed that it works with sort_by(key1, key2, ...).

I propose to add this to the Manual.

Based on a comment from #2466 I'm just going to submit a PR and wait patiently until someone merges it. No rush, since anyone who needs to know this will almost certainly eventually find the information.

[wader]

Great addition i think. I didn't know about it and based on the test cases when it was added 11965aa it is intentional. Kind of neat. Also the implementation is neat, the output from the filter is collected in an array [f] so the compare will be between to arrays.

[sergeysosivio]

im against var agrs.
i want better to have additional sort_by/2, where second parameter can define isDescending order

chaining those sort_by/2 with pipe can create efficient multi-sorting pipeline, without extra use of reverse|sort_by|reverse for not breaking stablesort

[ratijas]

Interesting. So in my case of parsing kscreen-doctor --json list of outputs (screens, monitors in human-speak) I has to do this to sort them first by enabled key and then by id:

outputs=(${(f)"$(
    kscreen-doctor --json |
    jq --raw-output '
        .outputs |
        sort_by([.connected | not], [.name]) |
        .[] |
        [.id, .name, .connected] |
        .[]
    ')"})

I'm a bit surprised that it didn't work as sort_by([.connected | not, .name]) without separate arrays, and I don't fully understand what is going on. But, hey, it works!

[wader]

I'm a bit surprised that it didn't work as sort_by([.connected | not, .name]) without separate arrays, and I don't fully understand what is going on. But, hey, it works!

Hi, you might want (.connected | not), .name else .name will index whatever .connected is.

$ jq -nc '{"connected": {"name": "b"}} | [.connected | not, .name]'
[false,"b"]

(but if .connected is bool i think you should have ende up with the error Cannot index boolean with string "name")