jq - select objects with given key name

Question

I've got an arbitrary structure with many levels, etc. I need to select all objects that contain a key named updateDate. How do I do that with jq? I came up with one way but it also produces errors on invalid data types when it visits a leaf which I have to grep out:

jq 'recurse(.[]) | has("updateDate")' | grep -Fv error

I don't really understand how to also check for types or leaves and I suspect there is a simpler way to achieve what I want?

Answer 1

In 1.4 you can just:

jq '..|.updateDate?'

If you're stuck with 1.3 you can use a longer program like so:

jq 'recurse(if type == "array" or type = "object" then .[] else empty end) | if type == "object" then .updateDate else empty end'

Answer 2

The accepted answer also produces null for every object that doesn't have the key.

What worked for me was:

jq '..|objects|.updateDate//empty'

The .updateDate//empty part means: if .updateDate is null (or false), skip it entirely.

This of course wouldn't work if you expect your key to have values of false or null. In that case, use this:

jq '..|objects|select(has("updateDate"))|.updateDate'

Answer 3

Not tested: how about jq 'recurse(.[]?) | objects | has("updateDate")' ?