Image onLoad event in isomorphic/universal react - register event after image is loaded

Question

In isomorphic rendered page image can be downloaded before main script.js file. So image can be already loaded before react register onLoad event - never trigger this event.

script.js

constructor(props) {
    super(props);
    this.handleImageLoaded = this.handleImageLoaded.bind(this);
}

handleImageLoaded() {
    console.log('image loaded');
} 

render() {
    return (
        <img src='image.jpg' onLoad={this.handleImageLoaded} />
    );
}

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Scenario 1 - image.jpg is bigger than script.js

In this scenario everything is working fine. Event is registered before image is finally loaded so in console is image loaded message.

---

Scenario 2 - image.jpg is smaller than script.js

This scenario you can see problem described at the beginning of post. onLoad event is not triggered.

---

Question

What can I do in order to trigger onLoad event in scenario 2?

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EDIT: Soviut answer implementation

To detect if image is ready on render you should check complete property on pure javascript img object:

constructor(props) {
    super(props);
    this.state = { loaded: false };
    this.handleImageLoaded = this.handleImageLoaded.bind(this);
    this.image = React.createRef();
}

componentDidMount() {
    const img = this.image.current;
    if (img && img.complete) {
        this.handleImageLoaded();
    }
}

handleImageLoaded() {
    if (!this.state.loaded) {
        console.log('image loaded');
        this.setState({ loaded: true });
    }
} 

render() {
    return (
        <img src='image.jpg' ref={this.image} onLoad={this.handleImageLoaded} />
    );
}

Answer 1

You could check the complete property on the image before applying the onload event.

if (!img.complete) {
    // add onload listener here
}

Answer 2

This is all a bit tidier with Hooks:

const useImageLoaded = () => {
  const [loaded, setLoaded] = useState(false)
  const ref = useRef()

  const onLoad = () => {
    setLoaded(true)
  }

  useEffect(() => {
    if (ref.current && ref.current.complete) {
      onLoad()
    }
  })

  return [ref, loaded, onLoad]
}

const SomeComponent = ({ src }) => {
  const [ref, loaded, onLoad] = useImageLoaded()

  return (
    <div>
      <img ref={ref} onLoad={onLoad} src={src} alt="" />
      {loaded && <h1>Loaded!</h1>}
    </div>
  )
}

Answer 3

Another way is to use ref and cover those both scenarios:

<img
  ref={(input) => {
    // onLoad replacement for SSR
    if (!input) { return; }
    const img = input;

    const updateFunc = () => {
      this.setState({ loaded: true });
    };
    img.onload = updateFunc;
    if (img.complete) {
      updateFunc();
    }
  }}
  src={imgSrc}
  alt={imgAlt}
/>