# TypeError when submitting a flag with custom content (require\_message flags)

**URL:** <https://meta.discourse.org/t/typeerror-when-submitting-a-flag-with-custom-content-require-message-flags/403133>\
**Category:** Bug\
**Tags:** fixed\
**Created:** [May 16, 2026, 2:45am UTC](https://meta.discourse.org/t/typeerror-when-submitting-a-flag-with-custom-content-require-message-flags/403133 "2026-05-16T02:45:08Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![cuo\_wu](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/cuo_wu/32/498442_2.png) [@cuo\_wu](https://meta.discourse.org/u/cuo_wu)\
**Post date:** [May 16, 2026, 2:45am UTC](https://meta.discourse.org/t/typeerror-when-submitting-a-flag-with-custom-content-require-message-flags/403133/1 "2026-05-16T02:45:09Z")

</div>

**Bug Description**

When a user selects a flag type that requires a custom message (e.g. `notify_moderators`, `notify_user`, or any admin-created custom flag with “Require message” enabled), fills in the message, and submits — the browser throws an uncaught TypeError and the flag is never submitted.

**Steps to Reproduce**

1. Visit any topic post
2. Click the flag button to open the flag modal
3. Select a flag type that requires a message (e.g. “Something Else” / `notify_moderators`, or any custom flag created in Admin → Flags with “Require message” enabled)
4. Type a message in the text area (long enough to pass the minimum length)
5. Click the submit button

**Expected behavior**

The flag is submitted successfully.

**Actual behavior**

The flag modal closes but the flag is not submitted. The browser console shows:

```plaintext
Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'act')
    at n.create (flag.js:24:8)
    at S.createFlag (flag.gjs:205:32)
    at S.takeAction (flag.gjs:196:12)
    at m.perform (reviewable-bundled-action.gjs:47:17)
    at ej._boundaryActionHandler (select-kit.js:685:34)
    ...

```

**Root Cause Analysis**

The crash originates in `Flag#create` (`flag.js:24`):

```js
create(flagModal, opts) {
  const postAction = this.postActionFor(flagModal); // returns undefined
  // ...
  postAction.act(...) // ← TypeError: Cannot read properties of undefined
}

```

`postActionFor` in `PostFlag` looks up the selected flag by numeric `id` inside `actions_summary`:

```js
// post-flag.js
postActionFor(flagModal) {
  return flagModal.args.model.flagModel.actions_summary.find(
    (item) => item.id === flagModal.selected.id
  );
}

```

The backend `PostSerializer` only includes a flag entry in `actions_summary` when at least one of `can_act`, `count`, or `acted` is truthy:

```ruby
result << summary if summary[:can_act] || summary[:count] || summary[:acted]

```

For `require_message: true` flags (which are all `notify_type: true`), `post_can_act?` sets `can_act: false` when `already_did_flagging` is true — i.e. the user has previously submitted any notify-type flag on that post. In that case the entry is absent from `actions_summary`, `postActionFor` returns `undefined`, and the crash follows.

Meanwhile `Post#flagsAvailable` (which controls what the user can select in the UI) uses the `actionByName` map built at page-load time, so the flag can still appear as selectable even after `actions_summary` no longer contains it.

**Secondary bug**

There is also a broken comparison in `flag.gjs`:

```js
const NOTIFY_MODERATORS_KEY = "notify_moderators"; // string

get notifyModeratorsFlag() {
  return this.flagsAvailable.find((f) => f.id === NOTIFY_MODERATORS_KEY);
  // ^ number ^ string — always false
}

```

`f.id` is a number but `NOTIFY_MODERATORS_KEY` is a string, so `===` always returns `false` and `notifyModeratorsFlag` is always `undefined`. This breaks the “Flag for Review” button logic in `flagForReview()`.

**Suggested Fix**

`PostFlag#postActionFor` should use the `actionByName` map (keyed by `name_key`) instead of searching `actions_summary` by `id`, consistent with how `TopicFlag#postActionFor` already works:

```js
// post-flag.js
postActionFor(flagModal) {
  return flagModal.args.model.flagModel.actionByName[
    flagModal.selected.name_key
  ];
}

```

And `notifyModeratorsFlag` should compare by `name_key` instead of `id`:

```js
get notifyModeratorsFlag() {
  return this.flagsAvailable.find((f) => f.name_key === NOTIFY_MODERATORS_KEY);
}

```

**Discourse version**

### 2026.5.0-latest

**Reproducible on**

- Latest `main` branch

---

_[View the full topic](https://meta.discourse.org/t/typeerror-when-submitting-a-flag-with-custom-content-require-message-flags/403133)._