How to create a JavaScript callback for knowing when an image is loaded?

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I want to know when an image has finished loading. Is there a way to do it with a callback?

If not, is there a way to do it at all?

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2020-11-22 05:45

If you are using React.js, you could do this:

render() {

// ...

 this.onImgLoad({ item })}
onError={() => this.onImgLoad({ item })}

src={item.src} key={item.key}
ref={item.key} />

// ... }

Where:

- onLoad (...) now will called with something like this: { src: "https://......png", key:"1" } you can use this as "key" to know which images is loaded correctly and which not.
- onError(...) it is the same but for errors.
- the object "item" is something like this { key:"..", src:".."} you can use to store the images' URL and key in order to use in a list of images.

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