Using useRef with PrismicNextImage

Developing with Prismic
1

Hi,
Lets say that I want to grab the image DOM element rendered by PrismicNextImage using the useRef hook from React. I tried to do the following:

const component = () => {
      const imgRef = useRef<null | HTMLImageElement>(null)

      return (<PrismicNextImage
          ref={imgRef}
          field={imageData}
        />)
}

but I got a TypeScript error that 'ref' doesn't exist on PrismicNextImage's props. Interestingly, when I console.log the imgRef.current in a useEffect, I get the image element rendered from the PrismicNext Image.

3

Hello Karim,

The error indicates that the ref prop is not recognized on the PrismicNextImage component's props.

To resolve this, you can use the forwardRef function from React to properly forward the ref to the underlying DOM element. Here's how you can modify your component:

import React, { useRef, useEffect, forwardRef } from 'react';
import { PrismicNextImage } from '@prismicio/react';

const PrismicNextImageWithRef = forwardRef<HTMLImageElement, any>((props, ref) => (
  <PrismicNextImage {...props} innerRef={ref} />
));

const Component = () => {
  const imgRef = useRef<null | HTMLImageElement>(null);

  useEffect(() => {
    if (imgRef.current) {
      console.log(imgRef.current); // This will log the image element
    }
  }, []);

  return (
    <PrismicNextImageWithRef
      ref={imgRef}
      field={imageData}
    />
  );
};

export default Component;

In this example:

  • PrismicNextImageWithRef is a new component created using forwardRef to forward the ref to the PrismicNextImage component.
  • The innerRef prop is used to pass the ref to the PrismicNextImage component.
  • The Component uses the imgRef to reference the image element.

This should resolve the TypeScript error and allow you to use the ref prop with PrismicNextImage.

If you have any further questions or need additional assistance, please let me know!

5

Thank you for your response. However, I'm still encountering the previous TypeScript issue with the forwardRef solution that you mentioned.

6

If the ref forwarding approach didn’t work, it’s possible that the PrismicNextImage component doesn’t properly forward refs or that it doesn’t directly expose the underlying img DOM element.

Here’s a more robust workaround to reliably grab the DOM element rendered by PrismicNextImage using Callback Ref with DOM Traversal:

We’ll leverage a callback ref to manually locate the img element in the DOM. Since PrismicNextImage renders an img element (or something similar), you can traverse its children to find the img.

import React, { useEffect, useRef } from 'react';
import { PrismicNextImage } from '@prismicio/next'; // Adjust based on your import path

const Component = () => {
  const imgRef = useRef<HTMLImageElement | null>(null);

  useEffect(() => {
    if (imgRef.current) {
      console.log('Image element:', imgRef.current); // Logs the <img> element
    }
  }, []);

  const setImgRef = (element: HTMLElement | null) => {
    if (element) {
      // Use querySelector to find the <img> inside the PrismicNextImage wrapper
      const img = element.querySelector('img');
      if (img) {
        imgRef.current = img; // Set the ref to the found <img> element
      }
    }
  };

  return (
    <div ref={setImgRef}>
      <PrismicNextImage field={{ src: 'example.jpg', alt: 'Example' }} />
    </div>
  );
};

export default Component;

Explanation:

  1. Callback Ref: Instead of assigning a ref directly to PrismicNextImage, we wrap it in a div with a ref that lets us manually locate the img element.
  2. DOM Traversal: Using querySelector('img'), we find the img element rendered inside PrismicNextImage and store it in imgRef.
  3. Why This Works: Even if PrismicNextImage doesn’t forward refs or provide direct access, its rendered output exists in the DOM, allowing you to query it.
1 Like
7

Thank you!

1 Like