How to add custom field to topic?

I tried to add custom field to Topic but doing it the same way as for category gives me error:

Property set failed: object in path "custom_fields" could not be found or was destroyed.

Example of how it works successfully for category:

Suggestions, anyone?

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I’m really stuck here :frowning:
I just don’t get it … what do I have to add to plugin.rb in order my plugin to have access to custom fields? As I understood, topics should already have custom field functionality by default.

I have code in pre-initializer…


      bumped_at_with_button: {
        get(date_value) {
          return new Date(date_value);
        set(value) {
          this.set('custom_fields.bumped_at_by_button', (value ? value.toISOString() : ''));
          return value;


I have following section in plugin.rb…

add_to_serializer(:topic_view, :bumped_at_with_button, false) {

But when setting value with…


… I get the message I pointed out in topic :frowning:

Help… anybody?

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Hello @Janno_Liivak,

As far as I know, TopicViewSerializer does not include a custom_fields field by default. With your call to add_to_serializer you could access directly to a field called bumped_at_with_button. However, If you want to access to that field through a custom_fields field, then I think you should change your code to something like:

add_to_serializer(:topic_view, :custom_fields, false) {

Thanks. It worked. But still … the value in setter function is always null. Could you point me in a right direction with

Topic.update(topic, props);

How should custom_fields.bumped_at_with_button be passed to props in order to be saved?

I’ve tried something, but it doesn’t work :frowning: In following code only bumped_at get’s saved to database… and sadly no new record in topic_custom_fields table.

import Topic from 'discourse/models/topic';

export default {
  actions: {
    clickButton(topic) {
      const current_date = new Date();
      topic.set('bumped_at', current_date);
      topic.set('custom_fields.bumped_at_with_button', current_date);
      const props = topic.getProperties('bumped_at', 'custom_fields');
      Topic.update(topic, props);
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Hey @Janno_Liivak

Did you find how to do it? I’m looking to the same at the moment


Yep. But as it was a long time ago don’t remember exactly what I did. I managed to build two plugins eventually. Maybe you can find your answers there?

Second one isn’t here but you can find it on github.

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Please note that sensitive info may be stored in topic custom fields - so don’t just dump them all out. Plugins should be selecting out just the fields they’re using.