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svelte-formula11/src/lib/components/LazyImage.svelte

43 lines
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Svelte

<script lang="ts">
import type { HTMLImgAttributes } from "svelte/elements";
import { lazyload } from "$lib/lazyload";
interface LazyImageProps extends HTMLImgAttributes {
/** The URL to the image resource to lazyload */
src: string;
}
let { src, ...restProps }: LazyImageProps = $props();
const blobToBase64 = (blob: Blob): Promise<any> => {
return new Promise((resolve, _) => {
const reader = new FileReader();
reader.onloadend = () => resolve(reader.result);
reader.readAsDataURL(blob);
});
};
const loadImage = async (url: string): Promise<any> => {
return await fetch(url)
.then((response) => response.blob())
.then((blob) => blobToBase64(blob));
};
const lazy_visible_handler = () => {
load = true;
};
// Once the image is visible, this will be set to true, triggering the loading
let load: boolean = $state(false);
</script>
<div use:lazyload onLazyVisible={lazy_visible_handler}>
{#if load}
{#await loadImage(src)}
<!-- Loading... -->
{:then data}
<img src={data} style="width: 100%" {...restProps} />
{/await}
{/if}
</div>