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Undefined slug.current and post.image when querying referenced vs referencing images

15 replies
Last updated: Jan 28, 2026
Kia ora! I have a follow up to a previous query - https://sanity-io-land.slack.com/archives/C9Z7RC3V1/p1619497015485200
I’ve successfully been able to reference the images I’m looking for, but I’m unable to use them in my front end for some reason! The only difference between this page and another is how I’m querying the images - in this gist, [slug].js is querying all image documents that reference this document (camera), and in [slug-1].js I’m querying a list of images that this document (collection) references.

There must be something I’m missing in how I process these queries and join the data, because next is giving me undefined for slug.current and post.image! Can anyone help?


https://gist.github.com/jenkshields/ec7a11fe3b0f830c40276c4343d33620
AI Update

Looking at your gist, I can see the issue! In [slug-1].js (the collection page), you're mapping over post.images but then trying to render post.slug.current and post.image outside the map function. The problem is that post in that context refers to your collection document, not the individual image documents.

Here's what's happening:

In your working [slug].js (camera page):

{post.photos.map((post) => {
  // Here 'post' is each individual photo document
  return (
    <Link href={`/photo/${encodeURIComponent(post.slug.current)}`}>
      <Image src={urlFor(post.image).auto('format').url()} />
    </Link>
  )
})}

In your broken [slug-1].js (collection page):

{post.images.map((post) => {
  console.log(post.image)
})}
// This div is OUTSIDE the map - 'post' here is still the collection!
<div>
  <Link href={`/photo/${encodeURIComponent(post.slug.current)}`}>
    <Image src={urlFor(post.image).auto('format').url()} />
  </Link>
</div>

The fix: Move your JSX inside the map function and return it, just like in your camera page:

{post.images.map((image) => {  // Rename to 'image' to avoid confusion
  return (
    <div sx={{
      '> a > div': {
        position: 'relative !important',
        height: 'auto',
        display: 'block',
        aspectRatio: '1 / 1',
      },
      '> a > div > img': {
        height: '100% !important',
        width: '100% !important',
        position: 'relative !important',
      }
    }}>
      <Link href={`/photo/${encodeURIComponent(image.slug.current)}`}>
        <a>
          <Image src={urlFor(image.image).auto('format').url()} layout="fill" objectFit="cover" />
        </a>
      </Link>
    </div>
  )
})}

The key changes:

  1. Added return statement inside the map
  2. Renamed the parameter from post to image to avoid confusion with the outer post variable
  3. Moved all the JSX inside the map function so it renders for each image

Your GROQ query looks correct - it's dereferencing the image references properly with "images": images[]->{image, slug}. The issue was purely in how you were rendering the data in React!

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