TypeError: Converting Circular structure to JSON

So I’m attempting to delete a row inside my psql database, a very simple structure with 4 rows + the auto ID:

CREATE TABLE public.tags
(
  id bigint NOT NULL DEFAULT nextval('tags_id_seq'::regclass),
  tag character varying(32) NOT NULL,
  description character varying(256) NOT NULL,
  server character(18) NOT NULL,
  added_by character(18) NOT NULL,
  CONSTRAINT tags_pkey PRIMARY KEY (id)
)

Attempting to reproduce the .del() example, I have the following code: knex('tags').where('tag', 'test').del();

I get the following error output to me: TypeError: Converting circular structure to JSON

I’m unsure what could cause this, and how to resolve it. Any ideas?

[tgriesser]

So this is what I’m guessing might be a similar problem to #1522, the async behavior isn’t kicked off unless the query is executed w/ then or similar.

If you put .then() on the end of the .del() it will executed the promise:

knex('tags').where('tag', 'test').del().then(data => {
  console.log(data)
}).catch(e => {
  console.error(e)
});

The TypeError: Converting circular structure to JSON shows up when you trying to JSON.stringify something which has a reference to itsself, which is probably happening when JSON.stringify a query building chain that hasn’t been executed, rather than its return result from the promise or callback.

[elhigu]

@eslachance I didn’t have that issue, because I didn’t ran the query, just checked what kind of SQL generates from it.

I still have no idea where in the code you are trying to convert object with circular dependencies to json string 😃 Great that you got your problem solved!

Functionality how queries are triggered is described in:

http://knexjs.org/#Builder http://knexjs.org/#Interfaces-Promises http://knexjs.org/#Interfaces-Callbacks http://knexjs.org/#Interfaces-Streams

pull requests to improve documentation are always welcome!