.jq

# jq functions

# return value only if not null (update only)
def replace(value):
	if . == null then null else value end;

# remove nulls
def denull:
	del(.[] | nulls);

# remove placeholder
def remove_placeholders:
	[
		. | to_entries[] |
		select(("<" + (.key | ascii_upcase) + ">") != .value)
	] | from_entries;

def case_mod_inner(case_mod_function):
	walk(
		if type == "object" then
			with_entries(.key |= (.[0:1] | case_mod_function) + .[1:])
		else
			.
		end
	);

# camelize keys
def camelize:
	case_mod_inner(ascii_downcase);

# pascalize keys
def pascalize:
	case_mod_inner(ascii_upcase);

# ref: https://stackoverflow.com/a/34282594/58678
def toxsv(transform_function):
	if length == 0 then empty
	else
		(.[0] | keys_unsorted) as $keys
		| (map(keys) | add | unique) as $allkeys
		| ($keys + ($allkeys - $keys)) as $cols
		| ($cols, (.[] as $row | $cols | map($row[.])))
		| transform_function
	end;

# csv
def tocsv:
	toxsv(@csv);

# tsv
def totsv:
	toxsv(@tsv);

# unflatten
# see https://stackoverflow.com/questions/57154970/how-to-get-inverse-operation-of-flatten-for-objects-using-jq/57155523#57155523
def un_flatten(delim):
	reduce to_entries[] as $kv ({}; setpath($kv.key|split(delim); $kv.value));

def unflatten:
	un_flatten(".");

def unflatten(delim):
	un_flatten(delim);