When publishing a value with a circular reference, a 'cyclic object value' error is thrown

When publishing a value with a circular reference, a ‘cyclic object value’ error is thrown. This is because of the serialization that happens to fill topicCache.

Code to reproduce:

const foo = {
  id: "foo",
  bar: ko.observable()
}
const bar = {
  id: "bar",
  foo: ko.observable()
}
ko.postbox.subscribe("foo", function() {
  console.log("foo was published");
})

ko.postbox.publish("foo", foo); // console: foo was published

foo.bar(bar);
ko.postbox.publish("foo", foo); // console: foo was published

bar.foo(foo);
ko.postbox.publish("foo", foo); // TypeError: cyclic object value

Is this something that can be solved by the library, or is it something I need to solve in my code?

[stijnherreman]

I’m currently using this workaround:

const serializer = ko.postbox.serializer;
ko.postbox.serializer = (object: any) => { return undefined; }
ko.postbox.publish("selectAdministration", this.administration);
ko.postbox.serializer = serializer;

I’m not using subscribeTo(...), or subscribe(...) with initializeWithLatestValue set to true, so I don’t think I’m breaking anything.

[frederikprijck]

Well eventually you might hit a point where you do need to serialize the object which includes a circular reference, and removing the serializer won’t help in that situation.

If that’s the case, you may want to look into Douglas Crockford’s cycle.js: https://github.com/douglascrockford/JSON-js

For KO postbox, you could easily create a wrapper around cycle.js and use it to serialize and deserialize your objects containing circular references.