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CREATE FUNCTION valid_json(json_val text) RETURNS boolean
LANGUAGE pljs IMMUTABLE STRICT
AS $$
try {
JSON.parse(json_val);
return true;
} catch(e) {
return false;
}
$$;
SELECT valid_json('{"foo": "bar"}'::TEXT);
valid_json
------------
t
(1 row)
CREATE FUNCTION get_key(key text, json_data json) RETURNS json
LANGUAGE pljs IMMUTABLE STRICT
AS $$
var val = json_data[key];
var ret = {};
ret[key] = val;
return JSON.stringify(ret);
$$;
CREATE TABLE jsononly (
data json
);
COPY jsononly (data) FROM stdin;
-- Call twice to test the function cache.
SELECT get_key('ok', data) FROM jsononly;
get_key
-----------------
"{\"ok\":true}"
(1 row)
SELECT get_key('ok', data) FROM jsononly;
get_key
-----------------
"{\"ok\":true}"
(1 row)
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