How can I update a React component's displayed image after an Axios call?

The issue is that you're not using React state to hold the "image" data. Simply assigning a new value to a variable doesn't trigger a re-render in React. To fix this, you should use the state (using useState in functional components) or this.setState in class components.

Below is an example using a functional component with useState and useEffect:

JSXCopied
import React, { useState, useEffect } from 'react';
import axios from 'axios';
import Avatar from 'path-to-avatar-component'; // update this import as needed

function ImageComponent({ id }) {
  const [image, setImage] = useState('');

  useEffect(() => {
    axios({
      method: 'GET',
      url: `http://localhost:${id}`,
      headers: { 'Content-Type': 'application/json' }
    })
      .then((response) => {
        setImage(response.data);
      })
      .catch((error) => {
        alert(error);
      });
  }, [id]);

  return (
    <div>
      <Avatar src={image ? `data:image/jpeg;base64,${image}` : ''} />
    </div>
  );
}

export default ImageComponent;

Explanation

• Using useState:
  The useState hook is used to create a state variable called image, which will hold your image data. When you update it using setImage, React knows to re-render the component.

• Using useEffect:
  The useEffect hook is used to run side effects such as your axios call. Setting [id] as the dependency ensures the effect runs when the id changes.

• Updating the State:
  In the .then() callback of the axios call, setImage(response.data) updates the image state. This causes the component to re-render and the updated image data is then used to update the <Avatar> component.

This approach ensures that your component is reactive to data changes from the server call.