-- maxProperties validation
-- shorter is valid
SELECT is_jsonb_valid('{"maxProperties":2}', '{"foo":1}');
 is_jsonb_valid 
----------------
 t
(1 row)

-- exact length is valid
SELECT is_jsonb_valid('{"maxProperties":2}', '{"foo":1,"bar":2}');
 is_jsonb_valid 
----------------
 t
(1 row)

-- too long is invalid
SELECT is_jsonb_valid('{"maxProperties":2}', '{"foo":1,"bar":2,"baz":3}');
 is_jsonb_valid 
----------------
 f
(1 row)

-- ignores arrays
SELECT is_jsonb_valid('{"maxProperties":2}', '[1,2,3]');
 is_jsonb_valid 
----------------
 t
(1 row)

-- ignores strings
SELECT is_jsonb_valid('{"maxProperties":2}', '"foobar"');
 is_jsonb_valid 
----------------
 t
(1 row)

-- ignores other non-objects
SELECT is_jsonb_valid('{"maxProperties":2}', '12');
 is_jsonb_valid 
----------------
 t
(1 row)