Get key names from JSON file recursively using jq

Question

I can get top-level JSON keys with jq as

jq 'keys'

E.g., see this question: Get key names from JSON file using jq

And I can enable recursion in jq:

jq '..'

As in: Recursive search values by key

But jq '.. | keys' returns jq: error at <stdin> string has no keys.

Answer 1

Just ignore keys when they are absent for some values in JSON:

jq '.. | keys?'

Answer 2

Ignore non-objects when inspecting for key names:

jq -r '.. | if type == "object" then to_entries[] | .key else empty end' "${LOCALAPPDATA}/Google/Chrome/User Data/default/Bookmarks" | sort --uniq
bookmark_bar
checksum
children
date_added
date_modified
guid
id
name
other
roots
synced
type
url
version