# Using LightDarkImg throws error

**URL:** https://meta.discourse.org/t/using-lightdarkimg-throws-error/384869
**Category:** Development
**Created:** [October 7, 2025, 8:47am UTC](https://meta.discourse.org/t/using-lightdarkimg-throws-error/384869 "2025-10-07T08:47:25Z")
**Posts on this page:** 1
**Showing post:** 1

<div class="post-metadata">

### Author: ![NateDhaliwal](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/natedhaliwal/32/313494_2.png) [@NateDhaliwal](https://meta.discourse.org/u/NateDhaliwal)
#### Post date: [October 7, 2025, 8:47am UTC](https://meta.discourse.org/t/using-lightdarkimg-throws-error/384869/1 "2025-10-07T08:47:25Z")

</div>

When using [`<LightDarkImg />`](https://github.com/discourse/discourse/blob/main/app/assets/javascripts/discourse/app/components/light-dark-img.gjs), I get a puzzling error that gives no actual indication to the route of the problem.

Error:

```plaintext
index.js:1755 
Uncaught (in promise) TypeError: eC(...) is not a function
    at index.js:1755:48
    at index.js:64:37
    at X (index.js:416:5)
    at k (index.js:62:16)
    at index.js:1759:46
    at index.js:64:37
    at X (index.js:416:5)
    at k (index.js:62:16)
    at m.get (index.js:84:60)
    at Array Iterator.next (<anonymous>)
    at A.getValue (index.js:244:86)
    at index.js:222:52
    at index.js:64:37
    at X (index.js:416:5)
    at k (index.js:62:16)
    at index.js:1841:47
    at index.js:64:37
    at X (index.js:416:5)
    at k (index.js:62:16)
    at Object.evaluate (index.js:807:13)
    at Object.evaluate (index.js:103:106)
    at tr.evaluateSyscall (index.js:2873:20)
    at tr.evaluateInner (index.js:2852:64)
    at tr.evaluateOuter (index.js:2849:10)
    at tH.next (index.js:4167:45)
    at tH._execute (index.js:4157:21)
    at tH.execute (index.js:4133:41)
    at tj.handleException (index.js:3450:19)
    at tR.handleException (index.js:3592:52)
    at tF.throw (index.js:3414:16)
    at G.evaluate (index.js:565:42)
    at tF._execute (index.js:3401:34)
    at tF.execute (index.js:3393:17)
    at tU.rerender (index.js:3610:8)
    at tq.render (index-BCp6wOJU.js:4639:55)
    at index-BCp6wOJU.js:4934:16
    at eX (index.js:2414:7)
    at tG._renderRoots (index-BCp6wOJU.js:4914:7)
    at tG._renderRootsTransaction (index-BCp6wOJU.js:4962:12)
    at tG._revalidate (index-BCp6wOJU.js:4995:10)
    at invoke (index.js:262:14)
    at m.flush (index.js:180:11)
    at g.flush (index.js:334:19)
    at q._end (index.js:762:32)
    at q.end (index.js:565:10)
    at q._run (index.js:806:14)
    at q._join (index.js:783:19)
    at q.join (index.js:605:17)
    at Array.<anonymous> (index-BCp6wOJU.js:4728:26)
    at q._trigger (index.js:860:21)
    at q._end (index.js:775:16)
    at _boundAutorunEnd (index.js:499:12)

```

My code:

```hbs
{{#if (and this.logoImg this.darkLogoImg)}}
  <div class="category-logo aspect-image">
    <LightDarkImg
      @lightImg={{this.logoImg}}
      @darkImg={{this.darkLogoImg}}
    />
  </div>
{{/if}}

```

The methods are as follows:

```js
  get logoImg() {
    if (settings.show_category_logo && this.args.category.uploaded_logo) {
      console.log(this.args.category.uploaded_logo.url);
      return this.args.category.uploaded_logo;
    } else if (
      settings.show_category_logo &&
      settings.show_parent_category_logo &&
      this.args.category.parentCategory &&
      this.args.category.parentCategory.uploaded_logo
    ) {
      return this.args.category.parentCategory.uploaded_logo;
    } else if (settings.show_site_logo && this.siteSettings.logo_small) {
      return this.siteSettings.logo_small;
    } else {
      return false;
    }
  }

  get darkLogoImg() {
    if (settings.show_dark_mode_category_logo && this.args.category.uploaded_logo_dark.url) {
      console.log(this.args.category.uploaded_logo_dark.url);
      return this.args.category.uploaded_logo_dark;
    } else if (
      settings.show_dark_mode_category_logo &&
      settings.show_parent_category_dark_mode_logo &&
      this.args.category.parentCategory &&
      this.args.category.parentCategory.uploaded_logo_dark
    ) {
      return this.args.category.parentCategory.uploaded_logo_dark;
    } else if (settings.show_site_logo && this.siteSettings.logo_small) {
      return this.siteSettings.logo_small;
    } else {
      return this.args.category.uploaded_logo; // If no dark mode logo is uploaded, use the normal logo
    } 
  }

```

I’m logging everything in the aforementioned LightDarkImg component (duplicated into my filesystem), and the image URLs print correctly. They even display correctly when in `<img>` tags.

Any ideas? Thanks.

---

_[View the full topic](https://meta.discourse.org/t/using-lightdarkimg-throws-error/384869)._